An Ontology Engineering Perspective to Create a Unifying Conceptualization of the Leadership Domain

Abstract

This article aims to propose a unifying conceptualization for the leadership domain utilizing ontology engineering to address conceptual ambiguity and information overlap. The approach involves identifying and defining structural, common, and underlying elements to organize leadership information. The methodology is based on a literature review guided by principles of ontology engineering. It focuses on collecting, analyzing, disambiguating, and synthesizing information to represent general elements in the leadership domain as categories, subcategories, and instances, including their relationships. The result is a unifying conceptualization comprising defined categories, subcategories, general instances, and relationships. This structure creates a taxonomic framework to organize the leadership’s domain information, classifying approaches, theories, models, styles, variables, characteristics, and organizational results. Expert validation confirms their suitability to represent the leadership domain in a general manner. Researchers can use it to understand and compare information, identify conceptual similarities and differences, and support knowledge dissemination within the leadership domain, reducing ambiguity and overlap.

1. Introduction

Leadership is currently recognized as a fundamental pillar for enhancing the performance of groups, organizations, and societies [1,2,3,4]. Furthermore, it is a pivotal determinant in environments where interpersonal interactions are crucial. Professionals from diverse fields have identified leadership as a central variable in the equation for defining organizational performance and success [5,6,7,8]. Given its relevance, the field has attracted researchers from various disciplines, resulting in a vast and rich body of academic work.

Over the years, research on leadership has been conducted using different approaches or lines of research. Each approach is associated with theories, models, styles, and variables, offering a particular perspective on leadership. These diverse approaches have led to a proliferation of information [9,10,11].

This proliferation of information generates conceptual ambiguity and information overlap. Conceptual ambiguity leads to imprecise definitions or unclear concepts [12]. Information overlap is evident when different perspectives use dissimilar words to name the same concept [9,11,13,14].

The absence of clear definitions for certain leadership concepts hampers conceptual and empirical progress [15,16]. For instance, the lack of a general definition for transformational leadership allows authors from specific perspectives to define it as a theory [8,17,18]. In contrast, other authors describe transformational leadership as an approach [19,20,21], although “theory” and “approach” are different concepts. Additionally, Yukl [22] criticized charismatic leadership theory for its conceptual ambiguity.

Furthermore, information overlap contributes to the appearance of similar styles in various leadership models, albeit with different names [9,14,23,24]. For example, Ohio State’s leadership model [25], Michigan’s leadership model [26], and Blake and Mouton’s Grid management model [27] all have styles that correspond to the same idea, but their names differ. Additionally, Banks et al. [9] and Legood et al. [28] highlight overlap in information, revealing remarkable correlations between supposedly distinct leadership styles, such as servant, ethical, and authentic leadership. Moreover, Van Knippenberg and Sitkin [16] criticizes the use of different labels within the field of leadership to name concepts with the same meaning.

To organize, clarify, classify, and synthesize the information in the literature to address conceptual ambiguity and information overlap in the leadership domain, various proposals have emerged employing conceptual frameworks [29,30], taxonomies [31,32], and meta-analyses [33]. However, many of these efforts have proven to lack a general or unifying approach. For example, conceptual frameworks have been developed that clarify concepts of specific leadership approaches [34], taxonomies focused on classifying and describing leadership behaviors or styles in particular situations [35,36], and meta-analyses that analyze only fractions of leadership styles [33] or delve only into specific application areas within the domain [37,38]. By limiting themselves to specific contexts or aspects, these proposals fail to offer a general and integrative view of the leadership field [39].

Establishing a unifying conceptualization or a general conceptual unification schema is imperative to address the challenges inherent in the leadership domain [40,41]. The solution proposed in this paper is to adopt methodological principles of ontology engineering to construct a unifying conceptualization of the leadership domain that allows for the organization and clarification of its knowledge. This approach allows for the identification of the structural, common, and underlying elements of the leadership domain.

By applying ontology engineering principles, it is possible to construct precise, clear, and integrative definitions of key leadership concepts. Furthermore, these principles ensure consistent terminology by assigning a single word to each concept and by establishing relationships between concepts to integrate different perspectives.

Furthermore, unlike meta-analyses, which are limited to quantitative data synthesis, ontology engineering performs semantic synthesis, integrating, organizing, and unifying knowledge based on the meaning of concepts, thereby achieving a logical coherence that statistical methods do not address [42].

While traditional taxonomies tend to focus on rigid relationships between concepts, ontology engineering allows for the modeling of complex relationships, providing a much more expressive and faithful representation of the complexity of the leadership domain [43,44].

Finally, unlike purely descriptive conceptual frameworks, ontology engineering produces formal schemes that eliminate ambiguity in definitions [45].

The methodological process followed in this research included knowledge acquisition through a literature review, the identification of structural, common, and underlying categories, and validation through expert judgment. This methodological process is based on the methontology framework proposed by [46] in ontology engineering.

The novelty of this work lies in the creation of a unifying conceptualization that organizes information on the leadership domain into seven fundamental categories: approach, theory, model, style, variable, characteristic, and organizational results. This structure not only clarifies definitions but also synthesizes overlapping styles into general instances. The developed conceptualization addresses conceptual ambiguity and information overlap in the leadership domain, providing a validated reference system for both researchers and organizational leaders.

To ensure its technical utility, the conceptualization is visually represented using the Unified Modeling Language (UML). The UML diagrams served as the basis for a web application. Furthermore, the unifying conceptualization of the leadership domain was validated by a panel of 12 experts using indicators of descriptive clarity, objective correspondence, relevance, viability, and coherence.

This article is organized as follows: Section 2 describes the methodological approach, based on ontology engineering, encompassing knowledge acquisition and expert validation. Subsequently, Section 3 presents the resulting conceptualization, analyzing its structural categories and subcategories, synthesizing leadership styles to resolve information overlap, and representing it using UML. The paper concludes with a discussion of the proposed representation and conclusions of the impact of the unifying conceptualization in the leadership domain.

The guidelines and stages that comprise the methodology of this study are presented below.

2. Methodology

Ontology engineering establishes an explicit and formal logic behind a domain’s organization. It allows for the integration of diverse viewpoints, enhancing information communication. Ontology engineering examines the methods and techniques employed for constructing conceptual unification schemes.

A conceptual unification schema organizes, clarifies, classifies, and synthesizes information in the literature, making experts share common agreements regarding ambiguity and information overlap within specific knowledge domains [47].

The ontology engineering perspective declares that an ontology functions as a conceptual unification scheme since it represents consensual and shared knowledge in a particular field [48]. Ontologies facilitate the taxonomic organization of information; thus, it is possible to identify more general concepts. Additionally, the ontologies contribute to constructing clear and detailed definitions, as well as the unambiguous descriptions of the concepts [49].

In ontology engineering, the construction of ontologies involves utilizing the following elements to represent a domain:

• Categories: embody a grouping of concepts sharing common characteristics.
• Subcategories: symbolize dividing a category into more specific groups of concepts.
• Instances: refers to each concept grouped into categories or subcategories.
• Relationships: denote various associations between categories, subcategories, and instances in a domain.

The development of an ontology using ontology engineering typically follows a structured, multi-stage process designed to ensure methodological rigor. It begins with domain delimitation, which involves clearly defining the domain under study (i.e., leadership) to establish a focused and coherent area of inquiry. This stage is followed by knowledge acquisition, where an expert team systematically collects and analyzes relevant literature from the domain to gather foundational information. The next stage involves identifying categories, subcategories, instances, and relationships that structure the knowledge’s domain. Subsequently, these elements are represented through graphical tools for visualizing and documenting the study domain’s structural, common, and underlying concepts to enhance clarity and aggregate formal structuring. Finally, the validation stage ensures the utility and alignment of the ontology with the real knowledge domain.

The methodology used in this study to develop a unifying conceptualization of the leadership domain from an ontology engineering perspective follows the guidelines of [46,47,48,50,51,52].

This research advances beyond these guidelines by transcending the application of ontology engineering in specific data integration tasks [47] or the modeling of organizational structures [51,52], to propose a unifying framework that resolves the problems of conceptual ambiguity and information overlap in the leadership domain. While the foundational methodologies provide the framework for the technical formalization of an ontology [46,48,50], this research advances by applying this technical framework to synthesize overlapping leadership styles and group the approaches, theories, models, variables, characteristics, and organizational results into structural, common, and underlying categories, thereby reducing conceptual ambiguity and information overlap. Furthermore, the study progresses in the rigor of statistical validation by employing a panel of experts who ensure descriptive clarity, objective correspondence, relevance, viability, and coherence between the unifying conceptualization and the reality of the leadership domain.

The following are the sequential methodological stages to develop the current proposal for the unifying conceptualization of the leadership domain.

2.1. Expert Team Constitution

The first stage consisted of creating an expert team to execute the methodological phases of this study jointly. These experts were selected through convenience sampling, considering their academic background, research experience, English language skills, and professional experience in the leadership domain. The team was comprised of five university professors affiliated with the Human and Organizational Development and Data Envelopment Analysis (DEA) Research Groups of the Faculty of Business Sciences at the Universidad Tecnológica de Pereira, Colombia.

It is important to specify that the team of five university professors was formed to broaden the scope of technical execution and initial semantic negotiation, during which concepts and relationships are identified for the conceptualization.

Choosing a team of five experts follows recent standards in ontological engineering, as evidenced by [53], who used five authors for a similarly complex document review. Wei et al. [54] further supports this by indicating that small, specialized teams of 5 to 11 members work best when high specialization in a domain is required. Having all team members from the same institution enabled rapid, iterative work on conceptualizing the leadership domain, similar to software development teams, where expertise and depth, rather than geographical diversity, are prioritized [55]. To mitigate the potential institutional bias, 12 external experts from various countries later validated the conceptualization (see Section 2.8).

2.2. Definition of a Work Corpus

Methontology framework proposes, as a starting point, identifying a body of knowledge that enables the extraction of information to build concepts, relationships, and instances.

This process involved identifying leadership-related documents. The information extracted from the documents served to formulate the unifying conceptualization.

At this stage, the expert team initially defined a preliminary set of scientific articles discussing leadership in a general manner. The initial scientific articles were exploratory and selected by the team’s expert judgment without following a systematic review protocol. This subjective selection or informal review aimed to identify representative information about leadership to serve as a starting point for the construction of the unifying conceptualization.

The initial subjective selection of articles responds to the need for having a general view of the domain before applying more formal and structured criteria. This stage is common in ontology engineering processes and allows for the capture of diverse knowledge before formalizing the ontology.

The initial scientific articles were selected from recognized scientific databases subscribed by the Universidad Tecnológica de Pereira, such as Scopus, IEEE Xplore Digital Library, ScienceDirect, Web of Science, and the ACM Digital Library, to ensure the academic quality of the material. In this process, the selection criteria focused exclusively on ensuring that the sources were indexed in recognized international databases and were part of scientific publishing circuits with established peer-review processes. This initial exploration resulted in eighty-two articles, which served as the basis for identifying fundamental notions within the leadership domain.

Ontology engineering guidelines utilize content analysis [56] as a deep reading technique to examine the contextual meaning of documents [57,58,59]. Content analysis aims to capture fundamental notions by identifying frequent and common words inside documents. Hence, content analysis allowed the experts to find words commonly and frequently appearing in the eighty-two initially selected articles. Notably, the experts retrieved words such as “approach”, “theory”, “model”, and “style” which became fundamental notions.

Subsequently, using fundamental notions strengthened the process of identifying a corpus or set of documents to construct a unifying conceptualization in the leadership domain.

A clear understanding of common and frequent words in the leadership domain helped the experts to conduct a formal literature review in Scopus, IEEEXplore Digital Library, Science Direct, Web of Science, and ACM Digital Library databases.

The formal review began with constructing a query string that incorporated the word leadership to align the equation with the central theme of the research. The word leadership was combined with fundamental notions previously identified in the informal review. Furthermore, the search encompassed words such as “taxonomy,” “characterization,” “ontology,” and “meta-analysis” to retrieve documents related to organizing, clarifying, classifying, and synthesizing information in the leadership domain.

Rather than directly addressing the entire literature corpus on leadership—which would entail excessive processing—it was decided to build the query string by accompanying the search with works that had already performed some synthesis, organization, classification, or taxonomic structuring on leadership. This methodological decision responds to a logic inherent to ontology engineering, which privileges sources that have advanced through preliminary stages of abstraction, classification, and formalization, thus facilitating the identification of relevant categories and hierarchical relationships. Furthermore, the inclusion of words such as “leadership,” “leadership theories,” “leadership approaches,” “leadership models,” and “leadership styles” responds to the need to maximize search sensitivity, considering the different ways authors may refer to leadership-related concepts in diverse contexts.

The query string is below.

(“leadership” OR “leadership theories” OR “leadership approaches” OR “leadership models” OR “leadership styles”) AND (“taxonomy” OR “characterization” OR “ontology” OR “meta analysis”)

Each database returned approximately 2000 results to the query string. Consequently, the expert team implemented a review protocol to restrict and refine the information exploration. The experts set forth two inclusion criteria:

a.

Select only documents that contain the designated words from the query string in their titles, abstracts, and/or keywords.

b.

Exclusively consider research and review articles, book chapters, and conference articles from engineering, business, management, accounting, and social sciences.

The inclusion criteria facilitated the retrieval of 1073 documents, corresponding to 765 research articles, 107 review articles, 88 book chapters, and 113 conference articles. The expert team then applied an approach based on ontology engineering principles to analyze these documents rigorously. Each document’s abstract, introduction, and conclusions were systematically examined in this phase to identify which documents contained theoretical and accurate information about the words in the query string. The rigorous analysis helped to select only 440 documents.

The 440 documents represented the work corpus for extracting information to create the unifying conceptualization for the leadership domain.

It is essential to clarify that the initial selection of 82 articles constitutes a standard pre-analysis or exploratory stage in content analysis and ontology engineering. Costa et al. [53] argue that objectivity in ontology engineering does not reside in the exploratory stage, but rather in the rigor of the review protocol subsequently applied to minimize human bias. In this research, initial subjectivity was controlled by applying inclusion and quality criteria to select the final 440 documents.

2.3. Identification of Structural, Common, and Underlying Categories in the Leadership Domain

The experts used the content analysis technique to examine the 440 selected documents.

The content analysis procedure involved depth reading of the corpus to identify emerging categories. The expert team manually conducted this process to capture the structure and meaning of the theoretical expressions. The domain expert team analyzed and resolved discrepancies in categorization using a triangulation protocol, comparing individual perceptions until reaching consensus.

The depth reading of the corpus drew in a Middle Out perspective to analyze the information as follows:

• Initially, it is essential to identify words to designate structural, common, and underlying categories. The chosen words are pivotal in establishing the foundational framework for a specific conceptualization [60].
• It is crucial to enhance the initial words as needed. The middle-out perspective allows the designation of new categories based on emerging information from analyzing and reviewing new documents.

In this study, the initial words were the fundamental notions (i.e., “approach”, “theory”, “model”, and “style”) retrieved during the informal literature review. Therefore, the initial words establish the foundational framework for the unifying conceptualization of the leadership domain.

Analyzing the 440 documents from the Middle Out perspective confirmed that fundamental notions maintained a high frequency of appearance in the work corpus. Moreover, the fundamental notions enabled the designation of structural, common, and underlying categories, thereby grouping instances or concepts that arose from the corpus was possible.

Likewise, the corpus analysis showed a frequent co-occurring of the “style” word with notions such as “characteristic”, “organizational result”, and “variable”. The co-occurring arises because the term “style” refers to a specific set of leader characteristics related to ways of acting or being. Furthermore, leader characteristics generate specific organizational results through interaction with situational variables.

The notions “characteristic”, “organizational result”, and “variable” facilitated the grouping of instances or concepts present in the analyzed corpus; therefore, these notions functioned as keywords for naming new structural, common, and underlying categories. Thereby, the experts selected the notions “characteristic”, “organizational result”, and “variable” to integrate the foundational framework for the unifying conceptualization of the leadership domain.

The previous analysis generated seven categories, grouping instances or concepts derived from the corpus analysis. These categories received the names “approach”, “theory”, “model”, “style”, “variable”, “characteristic”, and “organizational result”.

2.4. Development of Clear and Detailed Definitions to Unambiguously Describe the Categories in the Leadership Domain

The expert team utilized the Oxford English Dictionary to examine the general definitions of the words “approach”, “theory”, “model”, “style”, “variable”, “characteristic”, and “organizational result”. Additionally, the meaning given to these words within the leadership corpus helped to refine the categories’ definitions.

The study followed the recommendations of [46], on the words with multiple definitions in the corpus. Thus, the expert team utilized the commonalities of these words construct general and unambiguous definitions for the categories.

2.5. Identification of Subcategories and Synthesis of Information to Resolve Issues of Overlap

The content analysis technique helped to scrutinize the description of each instance or concept in each category. This stage consisted of identifying instances with similar characteristics regarding the collected textual information; then, the expert team grouped the similar instances into distinct subcategories.

The disaggregation of categories into subcategories facilitated the establishment of an organizational structure to arrange and classify information derived from the work corpus. The construction of subcategory names and definitions arose from expert knowledge and similarities in the instance descriptions grouped in each subcategory.

The experts found instances grouped into subcategories that used different names even though they described the same concept. This stage facilitated the identification of information with overlapping problems. Moreover, experts synthesized the information with overlapping problems into general instances with unified names.

2.6. Creation of Taxonomic Classification for the Set of Categories, Subcategories, and Instances in the Leadership Domain

Following ontology engineering guidelines, the expert team used the leadership domain knowledge and the information extracted from the corpus to identify three types of taxonomic relationships. These relationships allow for a structured representation of connections between categories, subcategories, and instances.

Inheritance relationships establish hierarchies connecting general categories to their subcategories or instances [61]. The phrase “is a type of” interprets the relationship. For example, the task-oriented style “is a type of” leadership style.

There are different forms of inheritance relationships:

• Disjoint decomposition where subcategories lack common instances.
• Exhaustive decomposition where subcategories can share common in stances.

Aggregation relationships depict a “container” category comprising other “component” categories [61]. The aggregation relationship relies on the principle of “consist of.” For example, leadership models “consist of” leadership styles. From an ontological perspective, this type of relationship allows categories to be broken down into their constituent elements.

Association relationships link categories beyond establishing inheritance or aggregation relationships [61]. Unlike inheritance or aggregation, the association relationship lacks a single meaning and can vary based on interactions between categories, thus requiring a contextual specification that precisely defines its nature. For example, leadership theories “come from” leadership approaches.

The relationships in the leadership domain express inheritance, aggregation, and association interactions between categories, subcategories, and general instances.

2.7. Representation of the Structural, Common, and Underlying Elements in the Leadership Domain

The group of categories, subcategories, general instances, and relationships identified in previous stages allowed the development of the Unifying Conceptualization of the leadership domain. Guidelines in ontology engineering suggested employing the Unified Modeling Language (UML) to visually represent the leadership domain’s structural, common, and underlying elements.

UML is a graphical tool for representing, visualizing, and documenting conceptual unification schemes [62]. UML is a standard, expressive, easy-to-learn, and easy-to-use language; therefore, UML is a valuable tool in this study.

2.8. Validation of the Unifying Conceptualization of the Leadership Domain

Campistrous and Rizo [63] created an expert criteria methodology that utilizes an expert group’s professional expertise and academic knowledge in a specific area to evaluate research results.

To select the group of experts validating the unifying conceptualization of the leadership domain, invitations were sent to university professors and professionals from various institutions, universities, and research groups specializing in leadership in English and Spanish speaking countries. Experts were selected based their professional, scientific, and academic level, ensuring that all those validating the conceptualization had the required professional, scientific, and academic qualifications. Twelve experts responded.

The use of twelve experts for the validation process is based on widely documented criteria of statistical optimization and qualitative rigor [63]. For example, Rand Corporation studies show the error rate drops with each expert added, but there is an inflection point at seven experts. Beyond this, accuracy gains are marginal and do not justify added costs or complexity. Thus, having 12 experts exceeds the critical threshold, supporting the transformation of individual subjectivity into group objectivity.

All the experts were fluent in English and worked in a high-impact scientific environment where English is the standard language. Following [63], the optimal number should not be sought at the risk of compromising the group’s qualifications. Likewise, although methods such as Delphi suggest larger groups for generic validation topics, current literature validates modestly sized panels when they achieve a balance between quality and cost, avoiding the inclusion of underqualified profiles that could compromise the reliability of the validation. It was also ensured that the experts had experience in administration, human development, organizational growth, and related fields, as shown in

Table 1. New experts’ group that validated the unifying conceptualization of the leadership domain.

No	Institution	Country	Professional Qualification, Scientific, or Academic Degree	Academic Degree	Years of Professional Experience	Years of Research Experience
1	Universidad de Valencia	Spain	Doctor	Psychology	25	25
2	Universidad de Valencia	Spain	Magister	EMJMD in WOP-P	1	3
3	Universidad de Valencia	Spain	Doctor	Doctor in Organizational Psychology	50	15
4	Universidad de Valencia	Spain	Doctor	Psychology	36	35
5	Universidad de Valencia	Spain	Magister	Master’s degree in Psychology—Pursuing a Doctorate in Human Resources Psychology	18	15
6	Center for Leadership and Management—CLG	Colombia	Magister	Master’s degree in Human Geography	16	10
7	Universidad Tecnológica de Pereira	Colombia	Doctor	Doctor of Management Sciences	28	25
8	Universidad Nacional de Colombia	Colombia	Doctor	Industrial Engineer, Doctor of Engineering: Industry and Organizations	28	20
9	Center for Leadership and Management—CLG	Colombia	Professional	International Business Management—Facilitator in Leadership & Management	3	1
10	Universidad Tecnológica de Pereira	Colombia	Magister	Master’s degree in Human and Organizational Development Management	40	20
11	Universidad de Puerto Rico	Puerto Rico	Doctor	Doctor of Education—Coordinator of the Leadership Program at the Universidad de Puerto Rico’s Educational Organizations	35	35
12	Center for Leadership and Management—CLG	Colombia	Magister	Master of Public Administration—Facilitator in Leadership and Management	15	6

.

Additionally, the group included academics and professionals from Spain, Puerto Rico, and Colombia, bringing an international perspective on leadership.

The validation process followed the methodology outlined by [63] and consisted of the following phases.

2.8.1. Assessment of Experts’ Competence

Equation (1) shows the competence coefficient ($K$) that helped to determine the experts’ competence.

$$K={\displaystyle \frac{1}{2}}\left(K_c+K_a\right)$$

(1)

where the knowledge coefficient ($K_c$) resulted from an experts’ self-evaluation wherein each expert rated their leadership knowledge on a scale of 0.1 to 1, with 0.1 corresponding to 10% and 1 representing 100%.

The argumentation coefficient ($K_a$) arose from a standardized table (see Table S1) proposed by [63]. The table helped the experts to score the influential sources in their comprehension of the leadership subject such as theoretical studies, experience, review of works by national and international authors, their knowledge and intuition.

Campistrous and Rizo [63] report that an expert’s competence coefficient K is high if it falls between 0.8 and 1, medium if it ranges from 0.5 to 0.79, and low if it is below 0.5. Besides, Campistrous and Rizo [63] state that only experts with a medium or high competence coefficient ($K$) are recruited in the next phase. Consequently, the criterion ensured that individuals had sufficient knowledge, skills, and experience to validate the proposal.

The knowledge coefficient (Kc) does not confer absolute competence certification based solely on individual perception. In line with other studies, such as [64], self-evaluation is used as a useful and complementary initial input to identify starting points, but not as a certifier of absolute expertise or technique. To neutralize the subjective bias of (Kc), the methodology proposed in [63] systematically balances it with the argumentation coefficient (Ka), which weights objective, verifiable evidence, such as theoretical studies and experience. By explicitly acknowledging the inherent limitations of self-evaluation, the research design ensures that only those individuals whose objective foundations (Ka) support their subjective perception (Kc) reach the competence levels required for validation. This weighted evaluation approach aligns with current evidence, where self-evaluation serves as an initial filter that must be balanced by objective evidence of performance and academic training to ensure the team’s objectivity.

2.8.2. Submit the Unifying Proposal for Evaluation by the Expert Criteria

During this phase, the selected experts examined the unifying conceptualization for the leadership domain.

Subsequently, each specialist took part in a survey to validate the unifying conceptualization, considering five indicators associated with specific statements. The indicators utilized were as follows:

Descriptive clarity: The categories, subcategories, and instances in the unifying conceptualization for the leadership domain are comprehensible, as well as the identified taxonomic relationships.

Objective correspondence: The unifying conceptualization represents a general schema associated with the leadership domain.

Relevance: The categories, subcategories, and general instances in the unifying conceptualization for the leadership domain are encompassing. This characteristic enables the grouping and synthesis of information to address issues of proliferation and information overlap.

Viability: The unifying conceptualization serves as a tool to assist researchers in classifying and ordering information, negotiating meanings, establishing consensus, as well as externalizing, comprehending, and improving the communication of knowledge.

Coherence: The unifying conceptualization is logical and consistent, and the definitions of its structural, common, and underlying elements are clear and unambiguous.

3. Results and Discussion

This section presents and discusses the results after applying the methodological steps described in the section Methodology. In addition, the section displays the results from validating the unifying conceptualization for the leadership domain using the expert criteria methodology.

3.1. Results of Building the Unifying Conceptualization for the Leadership Domain

Table 2. Structural, common, and underlying categories for the leadership domain.

Category	Definition
Approach	General perspective to analyze and explain the leadership domain.
Theory	Specific speculative knowledge or hypotheses to propose explanations within the leadership domain.
Model	Set of styles and variables to facilitate the theory abstraction.
Style	Concept to encompass the leader’s way of acting or being.
Variable	Concept with different meanings inside a specific context.
Characteristic	A quality that distinguishes and differentiates a leader. A characteristic confers a leader’s unique personality, style, manner, and behavior.
Organizational result	Effect and consequence inside an organizational environment.

shows the seven structural, common, and underlying categories identified for the leadership domain and their definitions.

The following are the findings of the content analysis considering the instances or concepts gathered in the categories of Table 2.

The “approach” category comprises two subcategories. Hence, the division facilitates grouping different approaches concerning specific and similar features.

Table 3. Subcategories in the “approach” category.

Category	Subcategory	Definition
Approach	Leadership as an attribute	Approach to explain leadership as an “attribute” that a gifted individual acquires or learns to influence others.
	Leadership as a process	Approach to explain leadership as a “process” with a collaborative and emergent structure arising from group interaction [65].

exposes the respective subcategories.

Besides, the “variable” category contains seven subcategories. The distribution enables grouping concepts or instances related to the particularities of the leader, the collaborator, the task, the leader’s operating environment, the organizational challenges, the organizational decisions, and the work teams.

Table 4. Subcategories in the “variable” category.

Category	Subcategory	Definition
Variable	Variables related to the leader	Variables about the leader’s qualities.
	Variables related to the collaborator	Variables about the collaborator’s qualities.
	Variables related to the task	Variables about the task’s characteristics.
	Variables related to the leader’s operating environment	Variables related to the characteristics of the environment in which a leader operates.
	Variables related to the organizational challenges	Variable related to the characteristics of organization’s challenges.
	Variables related to the organizational decisions	Variables related to the characteristics of organization’s decisions.
	Variables related to the work teams	Variables related to the characteristics of the work teams in organizations.

presents the seven subcategories.

Additionally, the “style” category is divided into eight subcategories to group styles that encompass similar ways of acting or being (see

Table 5. Subcategories in the “Style” category.

Category	Subcategory	Definition
Style	Task-oriented style	Leadership styles that combines ways of acting or being to achieve objectives, organization, structure, planning, control, monitoring of operations and problem-solving [66,67,68,69].
	Relationship-oriented style	Leadership styles that combines ways of acting or being to recognize human needs, respect collaborator’s feelings, support their work, improve the level of leader-member social-emotional interaction, and enhance impersonal [66,67,68,69,70].
	Medium task and relationship-oriented style	Leadership styles that combines ways of acting or being with a moderate orientation toward the tasks and relations.
	Low task and relationship-oriented style	Leadership styles that combines ways of acting or being with a minimal orientation toward the tasks and relations.
	High task and relationship-oriented style	Leadership styles that combines ways of acting or being with a high orientation toward tasks and relations.
	Change and transformational oriented style	Leadership styles that combines ways of acting or being to promote change, innovation, experimentation, learning, risk-taking, positive transformation of followers, organizational adaptability, and creative problem-solving.
	Value-oriented style	Leadership styles that combines ways of acting or being to promote moral and altruistic behavior within the organization, value development, service to others, authentic relationships, and ethical growth.
	Externally oriented style	Leadership styles that combines ways of acting or being to create interpersonal contacts, connection networks, and supportive relationships with people external to the organization.

).

A recurring problem during content analysis was the information overlap from instances grouped into subcategories of the “style” category. Information overlap occurs since certain styles refer to the same concept despite having different names in various theories or models.

Figure 1 shows two bands labeled Models/Theories and Leadership styles. The upper band displays several models and theories retrieved from the work corpus. Each model and theory have a distinctive color. For instance, the black color is for Hersey-Blanchard’s Situational leadership model, while the orange links to Blake and Mouton’s managerial grid model.

It is important to remember that different authors have proposed various labels to name styles in the leadership domain. Therefore, the unifying conceptualization considers eight subcategories to group styles associated with the same concept. Figure 1 shows the eight subcategories through circumferences in the Leadership style band.

Hence, Figure 1 facilitates the examination of the information overlap across diverse styles. For example, the directive, job-centered, authoritarian, dedicated, telling, and benevolent autocrat styles represent the task-oriented style despite having different names according to leadership models and theories.

Table 6. Example of synthesizing overlapping styles in general instances.

Instance	Overlapping Leadership Styles Synthesized into General Instances	Leader Characteristics Shared by Overlapping Styles	Organizational Results Shared by Overlapping Styles
Task-oriented style level II	Task-oriented Task management Job-centered Directive Dedicated Telling Personalized Benevolent autocrat Tells Autocratic I (AI) Autocratic I (AI)—Decision Transactional Out group Need for power Level I: Highly Capable Individual Authoritarian Authoritarianism Closing Leadership Behavior Resource allocator	Focus on production and meeting goals. Provide specific instructions on task execution and achievement of goals. Task-motivated. Authoritarian. Control compliance with regulations and the use of the organization’s resources, such as human, financial, material, and others. Skillful. With knowledge. Efficient work habits. Establish routines. Actively track errors. Focus on the present. Monitor operations, performance, and achievement of goals. Give orders. Planner. Demanding. Critical. Self-confident. Offer rewards. Sanctioning and correcting when objectives are not met. Remarkable sense of immediacy. Establish objectives, procedures, and responsibilities. Unilateral decision-making without considering other opinions. Imposition of the leader’s vision. Not very consultative. Use the available information in decision-making. Organizational. Grant relevance to differences in rank and position.	Scheduling and fulfillment of tasks according to the leader’s specifications. Work and resources assigned. Establishment of performance and behavior standards. Explicit activities and objectives. Demanding organizational culture, high control, and adherence to rules and regulations. Monitored operations. Planning and organizing activities. Emphasis on productivity. Structured working conditions. Efficient performance in the short term. Unilateral decision-making using available information. Unidirectional communication. Leader-follower relationship from boss to subordinate. Organizational stability preservation instead of promoting change. Organizational culture of discipline and loyalty in the work team.
Relationship-oriented style level II	Relationship-oriented Supportive Employee-oriented Human relations Developer Related Participating Socialized Joins Consultative II (CII) Consultative (C2) Impersonal Individual Benevolence Disseminator	The leader interacts with collaborators. The leader worries and prioritizes the well-being and growth of the collaborators. The leader establishes trust, mutual respect, support, and security. The leader attends the personal problems. The leader recognizes individual achievements, effort, and good work. The leader listens to the ideas, suggestions and needs of the collaborators. The leader promotes participation through the presentation of ideas and open discussions. The leader involves collaborators in decision-making. The leader shares and communicates problems and information with collaborators. The leader makes decisions through agreements with the collaborators. Supportive. Empathic. Friendly. The leader empowers the collaborators. The leader praises the collaborators. The leader accommodates to the opposition.	Positive interaction among collaborators. Conflict minimization. Creation of good interpersonal relationships. Work satisfaction. Organizational culture of trust and respect. Friendly organizational climate. High consideration among people. Participation and collaboration in decision-making. The leader and the collaborators make decisions through consensus. Increase in the probability of reaching a quality solution. Collectively obtaining ideas, suggestions, and alternatives. Create an emotional bond between leader and collaborator. Organizational cohesion and commitment. Open and bidirectional communication. Development of collaborators’ skills and strengths.
Medium task and relationship-oriented style level I	Middle of the road management III (Autocratic—Democratic) Suggests Consultative I (CI) Consultative I (CI)—Consult to the team Consultative (C1) consults the team members Controller	Fair, just. The leader shows confidence in the decisions. The leader likes to maintain the superior status. The leader promotes participation through the presentation of ideas and open discussions. The leader consults the opinions of collaborators before decision-making. Proactive. Not very delegative.	Collaborators with acceptable morale. Analysis of decisions to better understand their logic and implications. Balanced solutions that are more than adequate. Production and achievement of moderate goals. Balance between dedication to work and group integration. Organizational environment with emphasis on decision quality criteria rather than acceptance. Acceptable development. Efficiency in the organization of people, time, and resources. Makes decisions unilaterally according to the information provided from collaborators. Possible disagreements.
Low task and relationship-oriented style level I	VI (Liberal Democratic) VI (Liberal Democracy) Team centered (GII) Group II (GII) Group II (GII)—Delegating Collaborative (G)—shares Level 2: Contributing Team Member Negotiator Distributive Distributed Participative Separated Bureaucrat Abdicates Delegating	The leader shares and communicates problems and information with collaborators. The leader delegates problems, power, and responsibility. The leader encourages the collaborators to make consensual decisions within the established boundaries. Community. The leader prioritizes organizational objectives. The leader provides autonomy to collaborators. The leader values and enforces established principles. Confident in rules and procedures. The leader attaches importance to the mechanics of things. The leader listens to others and gives advice when asked for it.	Absence of ranks or hierarchies in the work teams. Elimination of authoritarianism, paternalism, technocracy, manipulation. Integration of the leader to the group as a member. Organizational culture of freedom for personal or team decisions. Collaborative work. Collectively obtain ideas, suggestions, and alternatives. The leader and the collaborators reach decisions through consensus. Knowledge exchange and transfer within the organization. Intuitive understanding between colleagues who work closely together. Self-managed teams. Controlled situations using rules and procedures.
High task and relationship-oriented style level I	Democratic Integrated Team leader Team Management Executive-level Selling Achievement Oriented In group Team Leader Level 3: Competent manager	Planner. Effective. Directing. Critical. Demanding. Rigorous. The leader supervises and coordinates collaborator activities. The leader establishes and provides collaborators with clear and challenging objectives. The leader communicates standards of performance and behavior that preserve discipline, ethics, and integrity. Motivational. The leader encourages creativity and innovation among collaborators. The leader inspires a sense of purpose. The leader is persuasive and influential. The leader supports collaborators. The leader promotes participation through the presentation of ideas and open discussions. The leader listens to the ideas, suggestions and needs of the collaborators. The leader involves collaborators in the discussion of objectives and decision-making. The leader trusts in the ability of the collaborators to reach high and challenging goals to solve problems. The leader evaluates and modifies the balance and composition of the group as needed.	Planning and organizing activities. Efficient organization of people, time, and resources. Clear direction towards the fulfillment of goals. Organizational culture of discipline and loyalty in the work team. The leader and the group of collaborators collectively make decisions through consensus. Collaborative work. Effective solutions both on a productive and personal level. Organizational culture of trust and respect among members of the organization. Open and two-way communication. Creation of good interpersonal relationships. Organizational cohesion and commitment. Achievement of challenging learning goals. Collectively obtaining ideas, suggestions, and alternatives.
Change and transformational oriented style level I	Change-oriented Change management-oriented Adaptive Willingness Level 4: Effective leader Entrepreneurship Entrepreneurial Disturbance handler Opening leadership behavior	The leader encourages creativity and innovation among collaborators. There is permission to perform a task in different ways. The leader encourages experimentation with different ideas. Monitoring of the external environment. The leader encourages risk-taking and generates enthusiasm. The leader establishes and provides collaborators with clear and challenging objectives. The leader guides to promote changes. The leader designs and manages change strategies, organizational learning, creative problem-solving and collaboration. The leader allows mistakes. The leader is prone to defying political situations. The leader manages the organization’s contingencies and problems. The leader manages corrective actions when the organization faces unexpected crises.	More creative, innovative, entrepreneurial, and adaptable environments. Design and implementation of new business projects. Clear and committed vision. Collaborators with the ability to adapt to the situations of a changing environment. High performance standards. Policies are consistent with changing situations.
Value-oriented style level I	Authentic Spiritual Servant Helpful Ethical Moral	Charismatic. Flexible. The leader empowers the collaborators. The leader is committed to collaborators and the common good. The leader cares about and prioritizes the well-being and growth of the collaborators. Sincere. Genuine desire to serve. Disinterested. Transparent. Self-conscious. Self-cultivator. Self-disciplined. The leader recognizes the importance of authentic interactions. The leader treats all collaborators, from the lowest to the highest level, with fairness, dignity, and respect. Optimistic. Transparent. Altruistic. The leader articulates and defends moral principles. The leader communicates and adheres to ethical values. The leader rewards ethical behavior. Spiritual. Humble. Kind. Integral, upright Trustworthy. Honest with oneself and with others.	Organizational culture of trust and respect. Organizational systems and policies that support moral and ethical behaviors. Creation of good interpersonal relationships. Environment that motivates the collaborators to reach their maximum potential through altruistic, ethical, and moral principles. Organizational cohesion and commitment. Climate of transparency, hope, and optimism. Creating a vision of service in the organization. Low work tension. Interpersonal values development.
Externally oriented style level I	External Liaison Spokesperson Figurehead	The leader manages through the connections and networks. The leader monitors the environment through others. The leader interacts with people outside the organization. The leader shares information with people outside the organization. The leader performs ceremonial functions, presides and represents the organization to visitors.	Creation of good interpersonal relationships. Creation of connection networks. Contacts with other people. External support from people capable of influencing the success of the organization. Clients and the public are aware of the organization’s official positions.

shows an example of overlapping leadership styles identified from the work corpus and synthesized in general instances. Identifying overlapping styles involved determining shared characteristics and recognizing which styles achieved similar or identical organizational results. The complete synthesis of overlapping leadership styles in general instances can be seen in Table S2.

The name of the general instances is associated with or refers to extreme or less rigid levels or degrees of application of the ways of acting or being of a leader.

In particular, the first column of Table 6 sets out how general instances may gather and named overlapping leadership styles.

The second column of Table 6 lists the various overlapping leadership styles identified in the work corpus. Meanwhile, the third and fourth columns summarize the overlapping styles’ shared characteristics and organizational results.

The unifying conceptualization proposal organizes, clarifies, classifies, and synthesizes information from the leadership domain. Furthermore, the proposal introduces a taxonomic structure to identify which concepts are more general than others.

Table 7. Example of the taxonomic structure with the categories and subcategories of the unifying conceptualization for the leadership domain.

Category	Subcategory	Instance
Approach	Leadership as an attribute.	Trait approach. Behavioral approach. Contingency or situational approach. Relational approach to leadership. Values-based leadership approach.
	Leadership as a process.	Relational approach to leadership. Values-based leadership approach.
Theory		Great man theory. Trait theory. Attribution or implicit leadership theory. Behavioral theory. Functional leadership theory. Contingency/situational theories. Leadership substitutes theory. The Leader-Environment-Follower Interaction theory. Transactional theory or Power and influence theories. Charismatic leadership. Cognitive resource theory. Role theory. Competency theory. Adaptive leadership. Vertical Dyad Linkage (VDL) or leader–member exchange (LMX). LMX-MMX leadership. Generative leadership. Transformational leadership. Transactional leadership. Servant leadership. Moral leadership. Authentic leadership. Spiritual leadership. Ethical leadership. Shared leadership or collective leadership. Cognitive resource theory. Paternalistic leadership. Ambidextrous leadership. Personal situation theory Path-goal theory.
Model		Ohio State Leadership model. Michigan leadership model. Blake and Mouton’s managerial grid. Action-centered leadership. Poliheuristic model. Fiedler’s contingency model. Hersey-Blanchard situational leadership model. Reddin’s 3D leadership model. Meta-leadership model. Vroom-Yetton model. Vroom–Jago model. Multiple-linkage model. Educational leadership. Leadership continuum. Full-Range leadership model. Level 5 leadership. Farh and Cheng’s PL model. Destructive leadership.
Style	Task-oriented style.	Task-oriented style level I Task-oriented style level II Task-oriented style level III Task-oriented style level IV
	Relationship-oriented style.	Relationship-oriented style—level I Relationship-oriented style level II Relationship-oriented style level III
	Medium task and relationship-oriented style.	Medium task and relationship-oriented style level I
	Low task and relationship-oriented style.	Low task and relationship-oriented style level I Low task and relationship- oriented style level II
	High task and relationship-oriented style.	High task and relationship-oriented style level I High task and relationship- oriented style level II
	Change and transformational oriented style.	Change and transformational oriented style level I Change and transformational oriented style level II Change and transformational oriented style level III
	Value-oriented style.	Value-oriented style level I
	Externally oriented style	Externally oriented style level I
Variable	Variables related to the leader.	Confidence level. Level executive effectiveness. Level of experience with problem-solving. Level of intelligence. Interpersonal orientation. Need for power. Self-efficacy. Self-leadership.
	Variables related to the collaborator.	Psychological maturity Work maturity. Worker’s personality Technical uncertainties. Knowledge-management level. Collaborative skills.
	Variables related to the task.	Task structure. Task condition. Task certainty.
	Variables related to the leader’s operating environment.	Leader-follower relationship. Leader-follower interaction frequency. Power of the leader’s position. Organizational characteristics. Resource management. External teamwork. Organizational climate and culture. Job satisfaction. Interpersonal stress.
	Variables related to the organizational challenges.	Leader’s information. Problem structure. Organizational goal congruence.
	Variables related to the organizational decisions.	Decision significance. Coworkers’ commitment to the decision value. Commitment probability. Decision speed.
	Variables related to the work teams.	Involvement and collaboration. Team experience. Competency in team. Possibility of organizational conflict. Member effort
Characteristic		Focus on production and meeting goals. Provide specific instructions on task execution and achievement of goals. Task-motivated. The leader interacts with collaborators. The leader worries and prioritizes the well-being and growth of the collaborators. The leader establishes trust, mutual respect, support, and security. Fair, just. The leader shows confidence in the decisions. The leader likes to maintain the superior status. The leader shares and communicates problems and information with collaborators. The leader delegates problems, power, and responsibility. The leader encourages the collaborators to make consensual decisions within the established boundaries. Planner. Effective. Directing. The leader encourages creativity and innovation among collaborators. There is permission to perform a task in different ways. The leader encourages experimentation with different ideas. Charismatic. Flexible. The leader empowers the collaborators. The leader manages through the connections and networks. The leader monitors the environment through others. The leader interacts with people outside the organization.
Organizational result		Scheduling and fulfillment of tasks according to the leader’s specifications. Work and resources assigned. Establishment of performance and behavior standards. Positive interaction among collaborators. Conflict minimization. Creation of good interpersonal relationships. Collaborators with acceptable morale. Analysis of decisions to better understand their logic and implications. Balanced solutions that are more than adequate. Absence of ranks or hierarchies in the work teams. Elimination of authoritarianism, paternalism, technocracy, manipulation. Integration of the leader to the group as a member. Planning and organizing activities. Efficient organization of people, time, and resources. Clear direction towards the fulfillment of goals. More creative, innovative, entrepreneurial, and adaptable environments. Design and implementation of new business projects. Clear and committed vision. Organizational culture of trust and respect. Organizational systems and policies that support moral and ethical behaviors. Creation of good interpersonal relationships. Creating connection networks. Contacts with other people.

shows an example of the taxonomic structure where the general categories bring together subcategories or instances with common characteristics. Moreover, Table 7 facilitates recognizing how the subcategories group more specific and similar instances. The complete taxonomic structure with the categories and subcategories of the unifying conceptualization for the leadership domain can be seen in Table S3. Besides, Table S4 shows the instance’s definitions of the unifying conceptualization for the leadership domain.

In this order of ideas, the proposal organizes and classifies the information extracted from the work corpus into the structural, common, and underlying elements of the leadership domain. Hence, the unifying conceptualization provides conceptual clarity and establishes a logical order for approaches, theories, models, styles, characteristics, organizational results, and variables.

UML facilitates a graphical representation of the categories, subcategories, general instances, and relationships derived from the unifying conceptualization of the leadership domain. UML employs a standardized and specific notation. (see Figure 2).

Figure 2, expressed using the UML graphical language, provides an overview of the structural, common, and underlying elements of the leadership domain. In this sense, the figure functions as a tool to clarify the general conceptual structure of this domain. The graphical representation of the unifying conceptualization of the leadership domain using the UML modeling language constitutes a general conceptual unification scheme that serves as a reference for developing theoretical frameworks.

Figure 2 uses rectangles to symbolize categories, subcategories, and instances. Moreover, Figure 2 expresses three forms of relationships.

Inheritance relationships connect general categories to subcategories or instances through lines with a triangle. The triangle is positioned at the end of the line and points toward the general category. For instance, Figure 2 shows the inheritance relationship that connects the general category “approach” with their subcategories “leadership as an attribute” and “leadership as a process.”

Lines with an unfilled rhombus symbolize aggregation relationships. The rhombus is positioned at the end of the line and points toward the “container” category, while the “component” category is at the opposite end. For instance, Figure 2 shows an aggregation relationship between the “Style” and “Characteristic” categories.

Finally, the solid lines indicate the association relationships. The name of the association appears next to the line. For instance, Figure 2 shows an association relationship where the “variable” category conditions the “style” category. The filled triangles denote the direction of the relationships.

Figure 2 shows the disaggregation of the “approach” category into two subcategories (“leadership as an attribute” and “leadership as a process”) through an inheritance relationship; thus, these subcategories are types of approaches. Besides, the inheritance relationship is an exhaustive decomposition type; hence, these subcategories may also share common instances despite having distinct instances. In this order, some approaches explain leadership exclusively as an attribute, while others interpret it solely as a process. Likewise, some approaches simultaneously define leadership as an attribute and a process.

For instance, the trait approach belongs exclusively to “leadership as an attribute” subcategory because it asserts that some individuals are intrinsically born or possess distinctive traits that qualify them as leaders. In contrast, the relational approach simultaneously belongs to both subcategories since it proposes two perspectives: the first postulates that leaders exhibit specific behaviors to foster interpersonal relationships with followers, while the second conceptualizes “leadership as a process” of social construction that emerges through general interactions and negotiation of social order among organizational members [70].

Furthermore, the association relationship of the “approach” category visually exposes that some approaches come from others in the leadership domain. To illustrate, contingency or situational, relational, and value-based approaches trace back to the behavioral approach. Through content analysis, examination of these approaches revealed that the behavioral approach was the pioneering perspective in asserting that a leader’s behaviors are pivotal elements that enhance effectiveness. Subsequently, the contingency or situational approach emphasizes how contextual factors influence a leader’s behaviors and shape leadership effectiveness. Meanwhile, the relational approach explores the leader’s behaviors to cultivate interpersonal bonds with followers [70]. Finally, the values-based approach claims that effective results arise when a leader’s behavior aligns with values [67,71].

Figure 2 declares an association relationship between the “approach” and “theory” categories to state that leadership theories come from approaches. For example, trait theory postulates that certain traits facilitate the discernment of a leader. Thus, trait theory stems from the trait approach. Moreover, the attribution or implicit leadership theory arises from trait and behavioral approaches. The attribution theory postulates that leadership is fundamentally a perceptual construct of the leader’s attributions as traits or behaviors [29].

The “theory” category has an association relationship, meaning that some theories come from others in the leadership domain. For instance, the authentic leadership theory incorporates elements of ethical leadership theory and servant leadership theory. Authentic leadership theory asserts that the leader actively cultivates an ethical environment that fosters self-awareness and an internalized moral perspective to achieve positive self-development and a commitment to serve others [72]. Besides, the ethical leadership theory declares that the leader has an ethical and moral compass to promote ethical environments [73,74]. Lastly, the servant leadership theory states that the leader operates with a deep self-awareness to respond to the altruistic motivation to serve others [71].

There is an association relationship between “theory” and “style” categories; hence, leadership styles come from theories. For instance, the value-oriented style arises from hypotheses of moral leadership [75], authentic [76], spiritual [77], servant [71], and ethical [73,74] theories. These theories posit that an effective leader embodies humility, possesses a moral and ethical compass to navigate diverse situations, distinguishes between right and wrong, consistently makes principled decisions, fosters positive development, and promotes a commitment to service for others.

Additionally, Figure 2 shows an association relationship between the “theory” and “variable” categories. Hence, it is possible to establish that variables come from theories. For instance, contingency or situational theory posits that leaders adapt their behavior to variables related to the task and the leader’s operating environment [75,78].

There are aggregation relationships among “style”, “variable”, and “model” categories to expose that leadership models contain styles and variables. To illustrate, Fiedler’s contingency model [75] incorporates the task-oriented and relationship-oriented styles besides indicating the variables related to the task and the leader’s operating environment.

Leadership models comprise styles and variables that come from theories; therefore, models also come from theories. Consequently, Figure 2 exposes an association relationship between the “theory” and “model” categories.

For example, behavioral theory assumes that individuals with the proper behavior can assume leadership roles. This assumption is central to the Ohio State leadership model and the Michigan leadership model. The former focuses on task-oriented or relationship-oriented leadership behaviors. The second focuses on leader behaviors differentiating employee-centered and job-centered actions [75].

The “model” category also presents an association relationship; some models come from others. For instance, the Ohio State leadership model and Michigan leadership model are the foundational frameworks of Fiedler’s contingency model.

Figure 2 illustrates the eight subcategories that group the overlapping styles in the leadership domain. There is an inheritance relationship between the “style” category and the subcategories. The inheritance relationship is a disjoint decomposition type; hence, the subcategories do not share common instances.

The aggregation relationship between the “style” and “characteristic” categories represents that leadership styles consist of characteristics that define a leader and differentiate him/herself from collaborators. Additionally, the “style” and “organizational result” categories have an association relationship (i.e., associated with) to denote that the application of leadership styles facilitates the achievement of organizational results.

For instance, the task-oriented leadership style implies that the leader focuses on production, achievement of goals and objectives, task motivation, and an authoritative personality, among other characteristics. Additionally, the task-oriented leadership style produces organizational results such as efficient scheduling, task accomplishment, high control, compliance with rules and regulations, and a demanding organizational culture.

Moreover, Figure 2 shows an inheritance relationship between the “variable” category and its seven subcategories through a disjoin decomposition; thus, there is an absence of common instances among the subcategories. To illustrate, the subcategory of variables related to the task aggregates instances that do not fall under another subcategory since it encompasses elements such as task structure, task condition, and task certainly.

The association relationship between the “variable” and “style” categories establishes that variables condition leadership styles to yield desired results. For example, the Hersey-Blanchard situational leadership model addresses variables related to the collaborator as a crucial element in determining the most effective leadership style [75]. The model highlights two variables: work maturity and psychological maturity. Thus, the task-oriented leadership style is appropriate when collaborators exhibit low work and psychological maturity levels, as employees have limited experience, knowledge, and problem-solving skills, display a restricted concern for other team members, exhibit a low receptivity to criticism, and demonstrate high distrust. In contrast, the low task and relationship-oriented style is suitable when collaborators exhibit high work and psychological maturity levels, as followers possess extensive experience, knowledge, and problem-solving skills; therefore, a leadership style that allows for autonomy, consensus decision-making, as well as a delegation of problems, power, and responsibility is appropriate in this case.

In summary, the current proposal of unifying conceptualization for the leadership domain, created through the methodological guidelines of ontology engineering, is a comprehensive reference system. The unifying conceptualization enables the integration of diverse perspectives into a single conceptual scheme; therefore, the proposal helps to clarify the structural, common, and underlying elements in the leadership domain.

The proposal of unifying conceptualization contributes significantly to reduce conceptual ambiguity. The definitions of categories, subcategories, and general instances arise from a methodology that allows clarifying and identifying similarities between concepts to unify interpretations. Moreover, the proposal differentiates approaches, theories, models, styles, variables, characteristics, and organizational results to facilitate the classification of information in the leadership domain.

Another noteworthy aspect of the unifying conceptualization is synthesizing the various overlapping leadership styles into general instances. Consequently, the proposal presents an alternative solution to mitigate the problems related to information overlap since several authors have called some leadership styles with different names.

Similarly, the classification and synthesis of information facilitate the construction of a taxonomic classification in the leadership domain through various types of relationships. The inheritance relationships linked general categories with their respective subcategories and instances. Aggregation relationships identified which categories constituted components of others. Besides, association relationships were instrumental in determining conceptual connections between categories.

The taxonomic classification is relevant because it serves to specify a domain of interest and define its essential structural components [79]. Moreover, the taxonomic system furnishes the conceptual schemas essential for generating new theories [80].

3.2. Validation Results in the Unifying Conceptualization of the Leadership Domain Using the Experts’ Criteria Methodology

The initial phase of the expert criteria methodology assessed the experts’ competence of twelve selected individuals. Eight experts showed a high competence coefficient (K), while the remaining four presented a medium coefficient (K). Therefore, the individuals had sufficient knowledge, skills, experience, or practice in leadership to validate the proposal.

Table 8. Coefficient of the Expert’s Competence.

Expert	Argumentation Coefficient (${\mathit{K}}_{\mathit{a}}$)	Knowledge Coefficient (${\mathit{K}}_{\mathit{c}}$)	Competence Coefficient ($\mathit{K}$)	Rating
1	0.8	0.9	0.85	High
2	0.8	0.3	0.55	Medium
3	0.8	0.7	0.75	Medium
4	1	0.8	0.9	High
5	0.9	0.4	0.65	Medium
6	0.9	0.7	0.8	High
7	0.9	0.8	0.85	High
8	0.8	0.7	0.75	Medium
9	0.9	0.7	0.8	High
10	0.8	0.8	0.8	High
11	0.9	1	0.95	High
12	0.9	0.7	0.8	High

exposes the detail information.

The twelve experts selected in the previous stage conducted the second phase of the methodology (see Section 2.8). Everyone completed a survey to assess indicators such as descriptive clarity, objective correspondence, relevance, viability, and coherence related to the unifying conceptualization of the leadership domain. The experts could classify each indicator into five rating levels: strongly agree (SA), agree (A), neutral (N), somewhat disagree (SD), and disagree (D).

Table 9. Absolute frequency.

Indicator	SA	A	N	SD	D	TOTAL
Descriptive clarity	6	4	2	0	0	12
Objective correspondence	11	1	0	0	0	12
Relevance	7	3	2	0	0	12
Viability	4	6	2	0	0	12
Coherence	7	4	1	0	0	12

shows the count of expert responses for each indicator regarding the rating levels.

Recognizing the absolute frequency enabled to calculate the cumulative frequency, that was essential for the validation process.

Table 10. Cumulative frequency.

Indicator	SA	A	N	SD	D
Descriptive clarity	6	10	12	12	12
Objective correspondence	11	12	12	12	12
Relevance	7	10	12	12	12
Viability	4	10	12	12	12
Coherence	7	11	12	12	12

shows the cumulative frequency.

Table 11. Cumulative relative frequency.

Indicator	SA	A	N	SD
Descriptive clarity	0.5000	0.8333	1.0000	1.0000
Objective correspondence	0.9167	1.0000	1.0000	1.0000
Relevance	0.5833	0.8333	1.0000	1.0000
Viability	0.3333	0.8333	1.0000	1.0000
Coherence	0.5833	0.9167	1.0000	1.0000

exposes the cumulative relative frequencies resulting from dividing the value of each cell in Table 10 among the number of experts consulted. Campistrous and Rizo [63] methodology recommends eliminating the last column of the “D” (disagree) rating level table because the aim consisted of evaluating five levels of assessment for each indicator. Then, the adjustment shifted the focus towards identifying four cutoff points to represent the values of the intervals defining each level of assessment (strongly agree, agree, neutral, somewhat disagree, and disagree).

Subsequently, Campistrous and Rizo [63] proposed to compute the inverse of the normal distribution curve (It pertains to employing a known probability to ascertain the corresponding critical z-value in a normal.) for each data point within the cells of Table 11. The process provided critical z-values (a point in the test statistic distribution that marks the boundary between rejecting and accepting a hypothesis) crucial for establishing the statistical intervals defining the assessment levels. This step beforehand aided in accurately assigning each indicator to its respective level of assessment.

Table 12. Statistical Intervals for rating levels.

Indicator	Strongly Agree	Agree	Neutral	Somewhat Disagree	Sum	Average	N-Average
Descriptive clarity	0	0.97	3.49	3.49	7.95	1.99	−0.23
Objective correspondence	1.38	3.49	3.49	3.49	11.85	2.96	−1.20
Relevance	0.21	0.98	3.49	3.49	8.17	2.04	−0.28
Viability	−0.43	0.97	3.49	3.49	7.52	1.88	−0.12
Coherence	0.21	1.38	3.49	3.49	8.57	2.14	−0.38
Sum	1.37	7.79	17.45	17.45	44.06
Cut-off points	0.27	1.56	3.49	3.49
Intervals	<0.27	0.27–1.83	1.83–5.32	5.32–8.81

presents the critical z-values. The ‘Sum’ column displays the sum of critical z-values for each indicator, whereas the ‘Average’ column denotes the mean value of the sum per indicator.

The ‘Cut-off Points’ row (in Table 12) displays the average of the critical z-values for each rating level. The ‘Intervals’ row delineates the ranges for each rating level. These ranges resulted by calculating the cumulative sum of each cut-off point.

Afterward, each indicator was allocated to a specific interval bounded by one of the cut-off points. To carry out this process, the calculation of the parameter N was necessary using Equation (2).

$$N={\displaystyle \frac{44.06}{25}}=1.76$$

(2)

The value 44.06 corresponds to the sum of the “Sum” column in Table 12. Likewise, the value 25 (in Equation (2)) arises from multiplying the number of rating levels (i.e., five) by the number of indicators (i.e., five). The “N-average” column in Table 12 displays values resulting from subtracting the average value per indicator from parameter N.

The process included comparing the (N-average) values for each indicator to interval boundaries set by cut-off points. The process aimed to determine the rating level for each indicator based on expert criteria (see “Intervals” row in Table 12).

In this case, the (N-average) values for each analyzed indicator were below zero. Therefore, all values were on the left of the 0.27 value associated with the “strongly agree” assessment level range. Hence, the five indicators consulted fell into the “SD” (strongly agree) range. Hence, the proposal of unifying conceptualization of the leadership domain exhibits descriptive clarity, objective correspondence, relevance, viability, and coherence.

4. Conclusions

The unifying conceptualization proposal presented in this study constitutes a comprehensive conceptual scheme that resolves the problems of conceptual ambiguity and information overlap in the leadership domain by applying the methodological principles of ontology engineering. Using ontology engineering allows for a more rigorous and formalized representation of knowledge, resulting in a more expressive and integrative conceptualization capable of synthesizing different theoretical perspectives and bringing greater clarity to the leadership domain.

A significant contribution of the unifying conceptualization proposal lies in reducing conceptual ambiguity since ontology engineering guidelines such as content analysis facilitated to identify and describe categories, subcategories, and general instances in the leadership domain.

Additionally, the unifying conceptualization has another significant contribution: the grouping and synthesizing of information in the leadership domain to mitigate overlapping problems. The unification effort helps to restrict the introduction of new notions unless they contribute to existing knowledge. Vilalta [81] asserts that progress in studying a domain comes from resolving contradictions between known concepts and reducing their number.

It is important to recall that the unifying conceptualization associates different overlapping leadership styles with leader characteristics and identifies the shared organizational results, responding to a need raised by [41]. Thus, the proposal provides substantial and significant data for the practical utilization of leadership. Zaccaro [82] asserted that leaders need a profound understanding of the leadership styles to guide their companies and human talent toward strategic objectives. Hence, comprehending results from different leadership styles [83] is pivotal to influencing organizational efficiency and employee motivation [84,85].

The unifying conceptualization proposal in this study offers a solid theoretical scheme that can guide future research in the leadership domain by providing a clear and integrative conceptual structure. This conceptualization can be used to design studies that avoid conceptual ambiguities, defining constructs more precisely. Future research can build on this conceptualization to conduct systematic reviews with homogeneous conceptual criteria or design explanatory models that integrate multiple perspectives. Furthermore, this type of unified structure promotes knowledge accumulation and facilitates comparison across studies, theoretical refinement, and the design of practical interventions based on a more articulated understanding of leadership. In this sense, when new leadership styles emerge, this conceptualization will allow comparing them with existing styles, analyzing their characteristics and the results they generate, and facilitating their proper classification, grouping, or, if relevant, recognizing them as a new construct within the leadership domain. In this way, the unifying conceptualization clarifies the current state of knowledge and acts as a catalyst for new, more comprehensive, cumulative, and theoretically grounded research.

UML diagrams assist software developers in identifying the system’s entities, attributes, interactions, and constraints. The authors of this paper constructed a web application grounded in the unifying conceptualization proposal using the UML diagram. The web application is available at http://201.131.90.155:9618/home, accessed on 1 June 2026. The web application is in Spanish and there are efforts to develop an English application version (The Spanish version of the web application was developed as an accessibility strategy for Spanish-speaking users, particularly in academic contexts in Latin America. Although the unifying conceptualization is based on English-language academic literature, the words were translated through a carefully reviewed conceptual equivalence process. This process included terminological validation by bilingual leadership experts and semantic comparison with the original sources, ensuring that the meanings and relationships defined in the original English corpus were maintained intact in the Spanish version. An English version of the web application is currently under development to facilitate parallel consultation and reinforce terminological consistency between the two versions).

Currently, researchers in the leadership domain can reference the web application to delve into concept definitions and identify taxonomic relationships among approaches, theories, models, and leadership styles. The web application also serves as a guide and resource for organizational leaders, assisting them in determining the most suitable leadership style to produce specific organizational results in a company. Furthermore, the web application aids in identifying leadership styles by considering leaders’ characteristics or organizational results. The authors of this paper regard the web application as a valuable tool for classifying and selecting the organization’s leaders based on the company’s desired goals.

Future works could adapt the unifying conceptualization proposal regarding the integration of insights from new approaches, theories, models, and leadership styles. It is essential to attempt the expansion of the unifying conceptualization proposal through an ontology evolution. Hence, the objective is to extract new categories, instances, relationships, and their respective definitions for integration into the proposal. Consequently, the adaptation process will facilitate the continual enrichment and strengthening of the unifying conceptualization proposal in the leadership domain.

The main challenge during the development of the unifying conceptualization proposal was to manually handle, analyze, classify, and synthesize information that comes from diverse approaches, theories, models, and leadership styles. Therefore, future works could consider the adaptation process through automatic or semi-automatic techniques such as natural language processing to swiftly and efficiently review new documents related to the leadership domain.

The validation of the unifying conceptualization of the leadership domain was conducted with experts from Spain, Puerto Rico, and Colombia to ensure its initial application in these contexts. The authors acknowledge this limited geographic representation as a limitation of the present study and propose, as future work, expanding the group to include experts from other geographic regions and linguistic areas to strengthen the global generalizability of the proposed conceptualization.