Digital Transformation and Administrative Harmonization Under the New EU Customs Reform: The Case of Post-Clearance Control in Bulgaria

Abstract

The digitalization of global supply chains and the increasing complexity of international trade have created both opportunities and challenges for customs administrations. The European Union has responded to these dynamics through the new EU customs reform, which aims to achieve full digital transformation and administrative harmonization across Member States. The study analyzes the preconditions for the reform through the lens of customs control, identifying its potential for modernization and the institutional challenges it poses. A quantitative survey was conducted among customs officers and economic operators in Bulgaria to assess their perceptions of the expected effects of the reform on communication, coordination, and control effectiveness. Using statistical methods, including the chi-square (χ²) test, Fisher’s exact test, and Cramér’s V test, the empirical results show statistically significant relationships between communication effectiveness, procedural consistency, and post-clearance control harmonization (p < 0.05). The strongest relationship is found between administrative communication and consistency in control implementation, confirming that harmonization depends not only on digital aggregation but also on institutional coordination mechanisms. The results show that the positive effects of the reform and the accompanying constraints are conditioned by administrative capacity, digital security, and sustainable trust between customs authorities and economic operators.

1. Introduction

The customs administration dynamics are functioning due to an increase in the volume of international supply chains, accompanied by high-tech development, ecological transition, geopolitical changes, and security risks. All these circumstances impact customs activity, exacerbating the need to improve control and catch up with the pace of development of business processes. The need for change is highlighted in numerous documents and recommendations to the European Commission (EC): reports of the European Court of Auditors (European Commission, 2021, 2023a), European Anti-Fraud Office reports, the report of the group of experts on the reform of the EU customs union (Wise Persons Group, 2022), “The Future of Customs in the EU 2040” by the Commission’s Joint Research Center (JRC) (Anda et al., 2020), and others. In response to these circumstances, the European Commission presents its proposal for the most ambitious and comprehensive reform of the EU Customs Union since its creation in 1968 (European Commission, 2023d). The reform aims to transform customs activities through digitization, data integration, and a centralized approach to customs control across the European Union.

The increasing complexity of international supply chains and the rapid digital transformation of global trade require modernizing customs control mechanisms to ensure adequate oversight while maintaining the free movement of goods. Post-clearance control is a mechanism that allows customs authorities to verify compliance and detect irregularities after goods are released, rather than relying solely on border controls (Anda et al., 2020). In parallel with the technological transformation, the reform provides guidelines for a management and operational reorganization (Junquera-Varela et al., 2022). It redistributes assessment and coordination tasks between the EU and national levels, shifts accountability through a higher level of data management, and changes the institutional environment in which post-clearance controls are planned, implemented, and evaluated.

The study focuses on the analysis of the envisaged changes in the EU customs reform through the lens of post-clearance control. It examines the opportunities for its development and the challenges it faces in the context of Bulgaria’s digital customs development. Examining the experience and possible consequences of the introduction of the reform in Bulgaria, on the one hand, provides an insight into a specific case of post-clearance control. On the other hand, it is an example of administrative harmonization across the EU. The reason for this is that the reform requires specific national adaptation, in line with standardized risk management approaches and enhanced inter-administrative coordination. It requires examining national structures for post-clearance control to summarize the possibilities for adapting organizational procedures and staff competencies to a data-driven supervision model. The example from Bulgaria, therefore, provides insight into how the European Commission’s desire to implement the reform for harmonization depends not only on the general European policy but also on the institutional arrangements and management capacity at the Member State level.

To empirically support the analysis, a survey was conducted among customs officials in the Republic of Bulgaria to explore their opinions on the upcoming changes, their readiness for the reform, and their perception of the opportunities and challenges related to post-clearance control. Based on statistical analyses, including correlations and p-values, the study identifies significant relationships. It provides practical recommendations for improving compliance, coordination, and communication among stakeholders in the customs control process.

The study’s contribution is that it considers the new EU customs reform not only from a regulatory and technological perspective but also as a process whose results depend on specific management conditions. On this basis, the empirical data cover two main groups of respondents: customs officers and economic operators. The article aims to identify the factors that have the greatest influence on the consistency and proper implementation of subsequent customs controls. In this way, the study adds scientific value by concluding that the practical harmonization of control activities depends on when the reform is introduced, based on digitalization and data exchange.

The main objective of the article is to analyze the impact of the new EU customs reform on customs post-clearance control mechanisms in Bulgaria. In this regard, the research hypothesis is tested that the new customs reform will provide many opportunities for the development of customs post-clearance control and will be a major driver of its upgrading and improvement after minimizing risks. Based on the outlined objective and the proposed hypothesis, the study addresses three important research questions.

RQ1: To what extent is the new EU customs reform expected to contribute to greater procedural consistency and effectiveness of customs post-clearance control within the EU and in Bulgaria?

RQ2: What practical and organizational challenges may the Bulgarian customs administration face when implementing post-clearance control under the new EU customs reform?

RQ3: Which specific practical difficulties in the Bulgarian context may limit or offset the expected positive effects of the reform?

The study examines the effect of the reform on the unification and improvement of post-control procedures, mainly through centralization, digitalization, and improved communication between national administrations. The main challenges identified are related to the customs administration’s resource and organizational capacity, resulting from digitalization, new data access requirements, and the loss of institutional autonomy. Finally, the article presents evidence based on expert assessments of respondents and covers the expected institutional effects and implementation conditions before the full implementation of the reform. On this basis, a systematic analysis of opportunities and challenges has been conducted, rather than measurable changes in the effectiveness of post-clearance control.

The article is structured as follows: Section 2 presents a literature review and a conceptual framework of customs post-clearance control as a key tool for supervision. Section 3 describes the research methodology applied in the study, including the design and conduct of the survey conducted among customs officials and economic operators in Bulgaria. It describes, in detail, the statistical approach used for data analysis and for interpreting significant statistical relationships. Section 4 presents the empirical results obtained from statistical analysis. The results of the study are reported, highlighting the perceptions of customs officials and businesses regarding the upcoming EU customs reform and identifying key areas of inconsistencies and communication gaps. Section 5 focuses on both opportunities to improve coordination, harmonization, and digitalization, as well as challenges related to administrative capacity, data security, and the potential loss of national autonomy. Section 6 summarizes the main results of the analysis and presents practical recommendations for increasing the effectiveness and adaptability of customs control.

2. Theoretical Background

2.1. The Concept and Evolution of Post-Clearance Control

Widdowson and Preece (2013) have identified post-clearance control as one of the most influential trade facilitation strategies available to border agencies. The authors define it as such because the post-clearance control allows the immediate release of imported cargo through the subsequent use of audit-based regulatory control. In its guidelines for risk management, through the implementation of a post-clearance control, the World Customs Organization (2012) defines the latter as “an effective tool for customs control, as it provides a clearer and more comprehensive picture of the transactions that are from Importance to Customs as reflected in international traders’ reporting”. At the same time, the instrument provides an opportunity for customs administrations to propose facilitation measures in the form of simplified procedures. Clark (2017, p. 51) concludes that the customs post-clearance control is “a key control methodology for facilitating the movement of goods through a risk-based selection process that moves the border management organization from a transaction-based process to an audit-based approach”. Undoubtedly, through post-clearance control, the customs authorities move the control impact from the control of the individual operation to a systematic control conducted through risk analysis and assessment of the overall activity of the economic operators. As D’Angelo (2023) points out, the customs post-clearance control is a general control measure that allows a 360-degree inspection and collection of information about the organizational, administrative, and internal procedures of the business operator, the primary purpose of which is to help the company to better comply with customs procedures.

Summarizing these definitions, post-clearance control can be defined as a structured verification of the physical and accounting records kept by economic operators (Ranchev, 2023) and their comparison with the customs formalities carried out for the import, export, and transit of goods. Its purpose is to establish the legality of actions and to improve the compliance between observed behavior and regulatory norms. Post-clearance control is increasingly used as a mechanism to reduce the burden of pre-clearance procedures and improve the effectiveness of overall customs supervision, using a variety of tools and data.

Despite the “look back” to the past, the post-clearance control asserts the future interest, as it facilitates learning lessons and taking measures for a more successful future passage through the relevant processes (Karklina-Admine et al., 2024). In the pre-clearance and current stage of the control activity, prevention can be achieved regarding the one-time transaction. Still, in post-clearance control, the customs authority has a view over the entire operator activity. It makes it possible to create analyses and conclusions about deviations and repeatable ones, based on which to derive proposals for the future activity of the object and to give detailed explanations and guidelines for actions that could not be done at the previous control stages to realize so comprehensively.

In the Bulgarian context, post-clearance controls are currently organized within specialized units of the Customs Agency, operating mainly on paper or semi-digital platforms. Although some electronic databases are used for risk assessment and document verification, real-time integration between accounting data, customs declarations, and analytical tools remains limited (Alavi-Borazjani et al., 2025). Communication between regional customs offices is hierarchically structured, but procedural inconsistencies in the application of control standards have been reported. This institutional environment provides a suitable basis for assessing how the new EU customs reform can transform existing operational practices and improve procedural coherence.

Despite the existence of a formalized regulatory framework and internal rules, differences in the extent and manner of post-clearance control implementation across the individual regional structures are observed in Bulgarian practice. These differences are due to factors such as uneven digital security, varying unit workloads, and variations in coordination mechanisms. Such an institutional environment creates the prerequisites for analyzing the extent to which the new customs reform can contribute to the real unification of control practices.

All these features of post-clearance control underline its importance as a basic form of control to apply in the conditions of digital transformation and transition from control over goods to control over data about goods. The critical role of post-clearance control in the conditions of customs reformation determines the need to explore the possibilities for its improvement. The digital transition and the rich toolkit offered by the new customs reform provide post-clearance control authorities with a wide range of options and a wide field of action in which control can develop its potential.

2.2. Core Concepts of the New EU Customs Reform

The European Commission’s (2023d) proposal for a new reform overturns the notions of customs activity, introducing powerful new digital tools and innovative technologies. The Commission calls for simplifying customs processes by digitizing and replacing data submission through traditional customs declarations with a more intelligent and data-driven approach (European Commission, 2023c). Risk-based and follow-up controls will offset the reduction in pre- and post-checks from the customs control process to ease international supply chains. The changes will inevitably lead to a strengthening of the control impact through customs post-clearance control, which will meet the new requirements and needs.

In practice, the proposal to create a single European Customs Agency formalizes the way to centralized management of customs control at the EU level rather than at the level of individual member states. The move will allow European customs to operate as a single administration, subject to a joint legislative framework and using a single electronic interface. Through the work of the European Customs Agency and the centralized processing of information, conditions are created to limit the duplication of efforts by member countries when two or more of them are involved in the customs processing of the same shipment. In its message to the European Parliament, the EC states that the single body will be tasked with the following main tasks: to bring together expertise and competence; to issue recommendations to national customs authorities for the exercise of control; to perform general risk management; to coordinate operational crisis management; to be a central customs intermediary for non-customs authorities; and to maintain the EU Customs Data Hub (European Commission, 2023b).

The central concept of the new customs reform is the creation of a single multifunctional interface at the EU level through which operational data exchange will be carried out electronically (European Commission, 2023d). Building on the already implemented EU-wide platform (familiar commercial interface) for entry summary declarations and the EU single window, the Commission offers all declarations and notifications—and thus all relevant import and export information—from importers, carriers, warehousers, e-commerce platforms, etc., to be presented to the EU and relevant national authorities through a central risk analysis platform and to be reused in subsequent processes (Lux, 2024). The Central Data Hub is designed to reuse the information stored in it, streamlining the process for all parties involved—business and customs authorities (Pickett & Wolffgang, 2023).

The technical implementation of digital transformation through the new EU customs reform is examined through the lens of three complementary aspects: Europeanization, multi-level governance, and differentiated enforcement. First, Europeanization refers to the process by which EU-level rules, tools, and governance concepts reshape internal administrative structures and practices. In the customs area, Europeanization extends beyond legal harmonization (Radaelli, 2023). It includes organizational adaptation, procedural standardization, and institutional training in response to centralized data management and shared risk-assessment mechanisms. The reform thus introduces stronger top-down regulation to promote procedural convergence and digital harmonization.

Second, the reform impacts on the logic of multi-level governance. Post-clearance control is embedded in vertically and horizontally interconnected administrative levels, where EU institutions, national customs administrations, and regional units interact continuously (Hooghe & Marks, 2009). In the context of centralized digital infrastructures and interoperable risk management systems (Kostova & Zhelev, 2025), communication and coordination become core institutional mechanisms, rather than additional tools. Their effectiveness determines whether harmonization becomes a coherent operational policy.

Third, differentiated implementation implies that uniform EU rules may yield uneven results due to differences in administrative capacity (Lambovska & Angelova-Stanimirova, 2025), digital security, organizational culture, and resource allocation (Zhelyazkova & Thomann, 2022). Therefore, the reform’s harmonizing potential is determined by institutional readiness and national-level governance mechanisms. In this regard, the example of the Republic of Bulgaria, on the one hand, provides an idea of the specific effects of introducing the new mechanisms, and, on the other hand, it addresses the systemic problems of the Member States, since we are in a single customs union.

The new customs reform introduces the concept of “Trust and Check”, which enhances the status of authorized economic operators (AEOs) to trusted and checked traders. The upgrade is designed to bring about positive changes and improvements, addressing the shortcomings of the previous AEO program. As highlighted in a special report of the European Court of Auditors 13/2023, the “Trust and Check” concept offers several benefits, including equal conditions for traders with an AEO, a standardized approach to measure program effectiveness, and the “untapped potential” to support business in the EU (European Court of Auditors, 2023). Under the “Trust and Check” concept, the reform ensures that goods can move through “green transit corridors” without formal interaction with customs and without additional administrative burden. It is made possible by the control measures exercised by customs authorities only, when necessary, thereby minimizing customs formalities and documentation required to place goods under the customs procedure.

The European Commission proposes to include in the new regulation an additional requirement, in addition to the previous criteria for AEOs: electronic access to the complete reporting kept by the operators, incl. customs, accounting, material, banking, and any other reporting related to its commercial operations, in connection with the provisions of Art. forty-eight of the Customs Code of the Union concerning the performance of post-clearance control. It will be supplemented by expanding the powers of the customs authorities performing a post-clearance control, namely, “to gain access to the operators’ systems to verify compliance with the obligation to provide or provide data to the Customs Location Centre EU data” (European Commission, 2023d).

2.3. Opportunities for the Development of Customs Post-Clearance Control

The transformation of customs policy in the context of the new EU reform presents both opportunities and challenges, depending on how its principles are implemented in practice. The success of the reform will depend on the ability of customs administrations to use new digital tools and harmonized procedures, while maintaining their operational flexibility (Krasteva-Hristova et al., 2025).

One of the most significant opportunities is the creation of a single European Customs Agency, which offers a framework for a fairer allocation of resources, unified training standards, and improved coordination between national and European authorities involved in cross-border trade (Antonini & Ioachimescu-Voinea, 2023). The centralized agency would improve administrative coherence and enable direct dialogue among customs administrations, leading to more effective customs post-clearance control and better coordination of enforcement policies.

The reform also introduces harmonization of control procedures, which is expected to reduce duplication of systems and administrative activities through a shared digital environment. Consolidating resources under a single management structure will reduce customs clearance times, improve efficiency, and limit the potential for corruption or arbitrary decision-making (Brazilii et al., 2025). Bringing together EU customs administrations under a single authority will also allow uniform sanctioning and decision-making practices, thus strengthening trust between Member States (Lyons, 2024).

Another option is to improve risk analysis. Currently, risk management is fragmented, with 27 different national approaches to assessing traded goods, creating opportunities for diversion, circumvention, and fraud (European Commission, 2023b, p. 15). The reform aims to create a new EU risk management framework involving Member States, the European Commission, the new customs authority, and market surveillance institutions. The framework will allow the collection and exchange of high-quality information on goods and economic operators, supporting more accurate risk profiling and consistent enforcement decisions (Sopilko et al., 2025). The aim is to share information on risky traders between customs administrations, avoiding the diversion of activities to jurisdictions with weaker supervision. Improved selectivity and harmonized data-driven risk assessment have a positive impact on strengthening enforcement capacity and should receive the same level of modernization as other elements of customs control (Smason, 2022).

The reform’s design aims to streamline control procedures and reduce administrative burdens. A single EU customs database will provide authorities with a comprehensive view of production processes and the international supply chain, allowing for more accurate traceability of origin, tariff classification, and customs value (Grainger, 2024). A transparent digital supply chain will make it easier to detect changes in trade patterns, determine anti-dumping duties, and verify non-preferential origin (Pickett & Wolffgang, 2023). Electronic access to business systems will significantly enhance control authorities’ monitoring capabilities. Once authorities have real-time access to accounting and inventory systems, they will be able to check compliance without additional documentation or physical visits automatically. Regular digital monitoring will reduce the administrative burden for both customs and operators, ensuring a more balanced and efficient enforcement system.

Finally, the reform facilitates the digitalization of controls and monitoring, providing a basis for transformation. In Bulgaria, customs post-clearance control remains mainly paper-based, with limited automation and only basic database use. The implementation of digital solutions will modernize workflows and strengthen risk-based supervision. Studies show that integrating digital tools into customs operations increases transparency, accountability, and efficiency. The application of advanced analytics, data validation software, and artificial intelligence will allow post-clearance control units to detect non-compliance, optimize monitoring, and move to a fully electronic compliance verification model (Gancheva et al., 2024). Through these improvements, post-clearance control will shift from a reactive to a proactive mechanism, enabling it to identify risks before they materialize.

2.4. Challenges for Customs Post-Clearance Controls Under the New EU Customs Reform

Despite these opportunities, the reform also introduces significant challenges that need to be addressed to ensure effective implementation. The creation of a centralized customs data hub will generate large volumes of data that require systematic processing and advanced analytical capabilities. Control authorities will need to adopt a data-driven approach, combined with automation and improved digital skills, to effectively deal with these new requirements.

A key challenge is the potential increase in control procedures following the redefinition of the authorized economic operator (AEO) in the “Trust and Check” trader concept. The change will require a review of all 17,338 existing AEO certificates across the EU, which represents a significant administrative effort (European Commission, 2023a). The European Parliament’s Committee on International Trade has also proposed shortening the monitoring interval for these operators from three to two years, based on risk levels and operational volume. While digital access will make supervision more seamless, the increased frequency of assessments will inevitably strain administrative resources and require additional staff time and expertise (Torello, 2020).

The removal of the possibility of automatic release of goods for free circulation will lead to more refund claims and corrections due to incomplete or missing documentation for operators who do not use the Trust and Check method. As Lux (2024, p. 530) notes, these discrepancies can lead to over- or under-valuation of customs value, increasing the workload for post-clearance control authorities. Similarly, the growing number of non-customs regulatory requirements—such as the General Product Safety Regulation (European Commission, 2021), the Forced Labour Regulation (European Commission, 2022), and the EU Carbon Border Adjustment Mechanism (European Parliament, 2023)—place additional responsibilities on customs administrations. Without regular training and access to up-to-date information systems, these overlapping obligations could slow down control processes and complicate operators’ compliance efforts.

Another significant problem is the loss of autonomy of national customs administrations. By establishing a centralized structure, Member States risk losing flexibility in setting national control priorities (Świerczyńska, 2023). While standardization is necessary, it should not stifle national specificities in trade flows and border conditions. Bulgaria needs to retain operational discretion to adapt EU-level standards to local realities. The success of harmonization, therefore, depends on balancing central authority with national adaptability.

The reform also poses a risk to data security. Giving customs authorities direct access to companies’ ERP systems, even with strict access protocols, carries potential cybersecurity vulnerabilities (de Carvalho Silva, 2025). Unauthorized data exposure or breaches would undermine trust between customs and business and slow down the deployment of digital infrastructure. To avoid such risks, the EU Customs Data Hub will require advanced encryption, multi-factor authentication, and standards for secure information exchange across Member States.

Finally, the success of the reform depends on the development of human capital. Continuous training and capacity building are integral components of the new system. Given the large number of customs officers in the EU, training and retraining will require a significant amount of time and resources. As the reform transforms control processes, staff will need to acquire digital literacy, analytical competencies, and familiarity with new technologies. Ensuring adequate staff training is crucial to maintaining effective controls during the transition period and beyond.

3. Materials and Methods

The study uses a quantitative research approach to examine the potential impact of the new EU customs reform on the functioning, structure, and effectiveness of post-clearance controls in Bulgaria. The methodological approach was chosen to achieve the study’s aim: to assess in advance the conditions under which the reform could improve post-clearance control, as well as the possible difficulties in its implementation. Therefore, the study uses survey data and statistical tests suitable for categorical responses, which allow us to establish whether there are significant relationships between key management factors and the perceived consistency of control. Thus, the results provide an empirical basis for discussing the practical prerequisites for a more uniform implementation of post- clearance control in the context of digitalization.

The methodology integrates descriptive statistical analysis to assess the relationships among administrative communication, procedural uniformity, and perceptions of the reform’s effectiveness among customs officers and economic operators. The methodological framework is built to ensure the reliability and validity of the results and to provide a statistically sound basis for conclusions on the opportunities and challenges in implementing post-clearance controls under the new reform.

3.1. Data Collection

The selection of the study’s general population is closely related to the institutional framework of post-clearance customs control in the Republic of Bulgaria. It covers two clearly distinguishable groups: (1) customs officers directly involved in post-clearance control activities and (2) economic operators subject to such controls within the national customs system. The selection of respondents is targeted and aligned with the research objective, which is to assess the institutional prerequisites for harmonizing post-clearance customs control in the context of digital transformation (Supplementary Materials).

Within the customs administration, the sample comprises 504 employees (out of a total of 734 employees working in post-clearance customs control), ensuring statistical representativeness and broad institutional coverage across hierarchical levels and regional units. Regarding economic operators, the population is dynamic and depends on the annual control plans and the enterprises’ risk profiles. The sample of 216 enterprises was selected systematically to cover participants in international trade of different sizes and sectors, enabling a comparative analysis between the administrative and business perspectives. In this sense, the sample claims to be probabilistically representative and analytically relevant to the studied management process, ensuring sufficient variability and institutional coverage for statistically sound conclusions.

The survey was conducted between March and June 2025 using structured questionnaires distributed electronically. To ensure internal consistency of the thematic blocks, reliability testing was performed using Cronbach’s alpha, which showed acceptable levels of internal consistency (α > 0.70) in the main constructs related to communication, coordination, and procedural clarity. The questionnaire design followed a structured logic aligned with the sub-hypotheses and was pre-tested among a pilot group to ensure construct clarity and validity. The survey instrument was developed in line with the objectives of the study and the existing literature on customs reform and control mechanisms. The questionnaires included closed-ended and semi-structured questions designed to measure perceptions of procedural clarity, inter-institutional communication, data management, digital readiness, and expected challenges after the reform.

The questionnaires are organized in thematic blocks that reflect the most important elements of post-clearance control in the context of the upcoming reform. The first group of questions describes the existence and application of internal rules and procedures; the second describes how respondents assess communication within the administration; the third describes coordination and exchange of information with other customs administrations; and the fourth describes the quality of communication between customs authorities and economic operators. The answers are given in a categorical form (“definitely yes” to “definitely no”), which allows testing the presence and strength of links between factors that support or hinder the consistent application of post-clearance control. For greater clarity regarding the survey instrument’s content logic, a summary of the main thematic blocks and measured variables used in the empirical analysis is presented in Table 1. The detailed wording of the questions is included in Supplementary S1 and S2.

Table 1. Structure of the survey instrument.

Thematic Block	Main Focus	Example Measured Variables
Internal rules	Existence and application of procedures	Procedural clarity, differences in application
Administrative communication	Communication between levels	Vertical coordination
Coordination at the EU level	Interstate cooperation	Information exchange, risk analysis
Communication with business	Interaction between administration and operators	Predictability, transparency

To ensure construct validity, the questionnaire was pre-tested among a pilot group of 20 customs officers. Feedback from the pre-test phase was used to refine the wording of the questions, remove redundant items, and confirm that all items accurately reflected the constructs under study. Responses were collected anonymously to avoid bias and ensure the validity of the conclusions.

3.2. Sample Characteristics and Scope

The sample of customs officials included respondents from all hierarchical levels and regional units of the Customs Agency of the Republic of Bulgaria, ensuring representation of both operational and managerial staff. The group of economic operators comprised companies of different sizes (small, medium, and large enterprises) operating in activities such as import/export, logistics, and customs representation.

The decision to focus on Bulgaria as a case study reflects both practical and theoretical considerations. As an EU Member State with an active role in cross-border trade, Bulgaria faces the dual challenge of harmonizing national practices with the Union’s customs policies while considering local operational specificities. The case study thus provides an appropriate perspective for assessing the real-world applicability of the principles of the EU customs reform.

3.3. Statistical Approach

The data were processed and analyzed using IBM SPSS Statistics 29. The study used both descriptive and inferential statistical methods, following a multi-stage analytical strategy. First, descriptive statistics are used to summarize respondents’ characteristics and identify general trends in perceptions of reform and post-release supervision practices. Second, to test the relationships between key categorical variables, including communication effectiveness, procedural consistency, and perceived differences in supervision, the study used the chi-square (χ²) test of independence. The choice of the non-parametric test was based on the nominal and ordinal data used to test the hypothesis. It was also considered whether there were statistically significant relationships between pairs of categorical variables. When the expected frequencies in the contingency tables were minor, Fisher’s exact test was used to assess the robustness of the results. It ensured an accurate estimate of the p-value, even with limited sample sizes across categories. Third, to assess the strength of the associations identified by the chi-square tests, the study used Cramér’s V, which quantifies the degree of association between variables on a scale from 0 (no association) to 1 (perfect association). The use of Cramér’s V allows for interpretation of the magnitude of the correlation beyond simple statistical significance, thus providing insight into the practical relevance of the results. A p-value threshold of 0.05 was used to determine statistical significance. Associations with p < 0.05 were considered significant, while those with p < 0.01 were interpreted as highly significant, confirming a moderate to strong association between the tested variables.

The dual approach, combining the chi-square test for independence with Cramér’s V, provides a comprehensive assessment of both the existence and the strength of the relationships among the factors under study. It is also in line with established practices in empirical research in the field of public administration and behavioral economics, where categorical perception data are analyzed to identify statistically significant behavioral patterns.

3.4. Research Hypothesis and Analytical Focus

The study is structured around a main hypothesis (H₁), which posits that the new EU customs reform will drive the modernization and improvement of post-clearance customs control. This hypothesis is detailed through three sub-hypotheses that focus on procedural coherence, organizational challenges, and context-specific constraints in Bulgaria. The relevance of the hypothesis for the current Bulgarian customs system lies in the identified inconsistencies in procedural application and communication gaps, which constitute the basic conditions the reform aims to address.

H₁. 

The new EU customs reform will provide significant opportunities for the development and improvement of customs post-clearance control and will act as a major driver for its modernization and refinement.

In order to achieve greater analytical clarity, the main hypothesis is decomposed into three sub-hypotheses.

H_1a. 

There is a positive relationship between the effectiveness of administrative communication and coordination and the perceived consistency in the implementation of post-clearance customs control.

H_1b. 

Organizational and resource constraints represent a significant challenge in the implementation of post-clearance control in the context of the new customs reform.

H_1c. 

Specific institutional and digital characteristics of the Bulgarian context may limit or modify the expected harmonizing effect of the reform.

In this way, the empirical analysis is directly linked to the study’s structural dimensions and follows procedural consistency, organizational challenges, and contextual constraints.

To assess the hypothesis, the analysis focuses on several key aspects derived from the survey responses.

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The presence of statistically significant relationships between established internal rules and perceived differences in customs control practices (Table 2);

Table 2. Correlational dependence between the established internal rules in customs and the opinion of the customs officials about the differences in the control exercised.

	Value	Df	Asymptotic Significance (2-Sided)	Exact Sig. (2-Sided)	Exact Sig. (1-Sided)
Pearson Chi-Square	4.495 a	1	0.034
Continuity Correction b	3.353	1	0.067
Likelihood Ratio	5.750	1	0.016
Fisher’s Exact Test				0.041	0.025
Linear-by-Linear Association	4.469	1	0.035
N of Valid Cases	504

^a One cell (25.0%) has an expected count of less than 5. The minimum expected count is 4.67; ^b computed only for a 2 × 2 table.

-

The impact of communication effectiveness at administrative levels on the consistency of control implementation (Table 3);

Table 3. Correlation dependence between the effectiveness of communication at individual administrative levels and the presence of differences in applied customs control.

	Value	Df	Asymptotic Significance (2-Sided)	Exact Sig. (2-Sided)	Exact Sig. (1-Sided)
Pearson Chi-Square	21.992 a	1	0.000
Continuity Correction b	18.095	1	0.000
Likelihood Ratio	14.421	1	0.000
Fisher’s Exact Test				0.000	0.000
Linear-by-Linear Association	21.861	1	0.000
N of Valid Cases	504

^a One cell (25.0%) has an expected count of less than 5. The minimum expected count is 1.62; ^b computed only for a 2 × 2 table.

-

The relationship between inter-agency coordination (both national and EU level) and the uniformity of customs enforcement (Table 4);

Table 4. Correlation between communication and coordination between customs authorities internationally and within the EU.

	Value	Df	Asymptotic Significance (2-Sided)	Exact Sig. (2-Sided)	Exact Sig. (1-Sided)
Pearson Chi-Square	6.310 a	1	0.012
Continuity Correction b	4.436	1	0.035
Likelihood Ratio	4.830	1	0.028
Fisher’s Exact Test				0.026	0.026
Linear-by-Linear Association	6.273	1	0.012
N of Valid Cases	504

^a One cell (25.0%) has an expected count of less than 5. The minimum expected count is 1.62; ^b computed only for a 2 × 2 table.

-

The level of communication between customs authorities and the business community (Table 5).

Table 5. Correlation dependence between the applied control and the level of communication between the customs authorities and the business.

	Value	Df	Asymptotic Significance (2-Sided)	Exact Sig. (2-Sided)	Exact Sig. (1-Sided)
Pearson Chi-Square	6.337 a	1	0.012
Continuity Correction b	5.116	1	0.024
Likelihood Ratio	6.183	1	0.013
Fisher’s Exact Test				0.019	0.013
Linear-by-Linear Association	6.299	1	0.012
N of Valid Cases	504

^a Zero cells (0.0%) have an expected count of less than 5. The minimum expected count is 7.07; ^b computed only for a 2 × 2 table.

These indicators were selected because they represent the operational dimensions most directly affected by the upcoming reform: organizational coherence, communication effectiveness, and administrative capacity. By testing the relationships among these dimensions, the study assesses the extent to which the digital and structural changes of the reform are likely to support or weaken the customs post-clearance control system in Bulgaria.

The obtained statistically significant relationships, confirmed by the chi-square and Cramér’s V coefficients, provide sufficient and reliable empirical evidence in support of the hypothesis and serve as an analytical basis for the discussion and policy recommendations presented in the following sections.

3.5. Methodological Rigor and Limitations

The combination of survey-based quantitative analysis and logical statistical testing ensures both internal and external validity of the study. Internal validity was achieved through consistent data collection procedures, representative sampling, and the use of validated statistical tests. External validity is supported by the comparability of the Bulgarian customs context with the wider EU customs structures, allowing the findings to be generalized to similar administrations within the Union.

A limitation of the study is its reliance on respondents’ expert assessments, perceptions, and expectations regarding the upcoming implementation of the reform. Therefore, the findings represent a preliminary assessment of the expected institutional effects, rather than a direct measurement of the implemented administrative change. Future research should complement the evidence based on perceptions with indicators of administrative efficiency, recovery efficiency, error probability, and interoperability indicators once the reform instruments are in place.

The study also has some limitations. It is based on self-reported data, which may be influenced by subjective perceptions, and, because χ² and Cramer’s V are not reliable for continuous variables, the study does not capture potential causal dynamics or relationships involving continuous variables. Future research could extend the framework using multivariate regression or structural equation modeling to capture interaction effects more fully. The existence of these limitations does not negatively affect the chosen methodology, which is based on empirical evidence to assess the practical consequences of the EU customs reform and to derive practical recommendations for improving post-clearance control mechanisms in Bulgaria.

4. Results

The empirical results present the statistical analysis of the survey conducted among customs officials and economic operators in Bulgaria. The results focus on four key aspects that reflect the effectiveness and consistency of customs post-clearance control in the framework of the upcoming EU customs reform:

(1)

The existence and implementation of internal rules and procedures.

(2)

The effectiveness of communication at administrative levels.

(3)

Coordination between customs authorities at the national and European levels.

(4)

Communication between customs authorities and businesses.

The study primarily focused on investigating the relationship between the attitude of customs officials from the units for post-clearance control and the processes of implementing their control functions. A key aspect of customs post-clearance control is customs officials’ availability and adequate implementation of internal rules and procedures at the relevant hierarchical levels. The survey found that 88% of respondents stated that clear rules and procedures were in place to implement customs post-clearance controls. Despite the existence of clear rules and procedures in customs, the study’s results showed differences in their application during customs post-clearance control.

The chi-square value of 4.495, with a p-value of 0.034, indicates a statistically significant relationship between the presence of internal rules and perceived differences in the applied control. Although 88% of customs officials confirmed the presence of clear internal procedures, nearly half (9.5% “definitely yes” and 39.3% “rather yes”) acknowledged differences in their application between customs offices. Among economic operators, the divergence was even more pronounced, with 58.3% stating “definitely yes” and 25% “rather yes” regarding inconsistencies in control practices.

The second relationship examined was between communication effectiveness within different administrative levels and the uniformity of post-clearance control.

The chi-square value of 21.992 (p < 0.001) indicates a highly significant relationship between the two variables. The finding suggests that internal communication within the customs hierarchy directly affects the consistency of control practices. Respondents identified communication gaps as one of the main factors leading to discrepancies in the implementation of post-clearance control between regional customs offices.

The next aspect explored was the relationship between the coordination and communication of customs authorities at the EU level and the uniformity of customs control practices.

The chi-square value of 6.310 with a p-value of 0.012 confirms a statistically significant relationship between coordination among EU customs authorities and control consistency. It implies that insufficient international communication and the lack of harmonized risk analysis procedures contribute to variations in enforcement standards and to delays in detecting irregularities across Member States.

The study also tested the link between the perceived quality of communication between customs authorities and the business community and the consistency of post-clearance control.

The chi-square value of 6.337 (p = 0.012) indicates a statistically significant association between communication with economic operators and uniform control practices. The findings demonstrate that better communication between customs and businesses is associated with higher procedural transparency and greater predictability in post-clearance control operations.

Beyond correlation analyses, the survey explored broader perceptions of the upcoming reform among customs officials. The results revealed overwhelmingly positive expectations regarding the effects of digitalisation and structural unification.

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A total of 60.9% of respondents believe that the new European Customs Agency will help to harmonize customs procedures across Member States.

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A total of 53.1% agree that the reform will promote the establishment and functioning of a single EU customs system.

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A total of 88% expect digitalization to optimize customs processing of goods, while 85% expect formalities to be simplified, and 75% foresee improved efficiency of customs controls.

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A total of 82% of respondents believe that the reform will improve the accuracy of revenue collection, 74% expect fewer technical errors, and 78% expect higher data quality.

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A total of 65% of respondents expect the reform to reduce fraud attempts.

Regarding the new requirement for electronic access to traders’ systems, 39.4% of economic operators answered “definitely yes”, and 48.5% answered “rather yes”, indicating a willingness to share more electronic data with customs authorities. None of the respondents answered “definitely no”, demonstrating an overall supportive attitude towards the digitalization of customs procedures.

The overall results confirm that several key interrelationships in the customs control process are statistically significant at the moderate to strong levels. Specifically:

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Internal procedural clarity correlates significantly with control consistency (p = 0.034).

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Communication across administrative levels strongly influences procedural uniformity (p < 0.001).

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International coordination and communication within the EU show a significant positive relationship with the harmonisation of control practices (p = 0.012).

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Effective communication between customs and business increases transparency and consistency (p = 0.012).

These findings empirically support the study’s hypothesis that the new EU customs reform, by emphasizing digital integration and centralized data management, can address procedural and communication inefficiencies in post-clearance controls. To enhance analytical clarity, Table 6 summarizes the statistically significant associations identified in the empirical analysis.

Table 6. Summary of statistically significant associations.

Association Tested	χ2	df	p-Value	Cramér’s V	Strength of Association	Interpretation
Clarity of internal rules × perceived differences in post-clearance control application	4.495	1	0.034	0.09	Small	Statistically significant association indicating that clearer internal rules are related to lower perceived inconsistencies in control practices.
Effectiveness of administrative-level communication × consistency of post-clearance control	21.992	1	0.001	0.21	Moderate	Highly significant association suggesting that stronger vertical communication is linked to more consistent application of post-clearance control.
Coordination and communication with other EU Member States × consistency of post-clearance control	6.310	1	0.012	0.11	Small to Moderate	Significant association indicating that effective cross-border coordination supports harmonized control practices.
Customs–business communication × predictability/consistency of post-clearance control	6.337	1	0.012	0.11	Small to Moderate	Significant association suggesting that improved interaction with economic operators contributes to perceived procedural consistency.

Note: χ² = Pearson chi-square; df = degrees of freedom; Cramer’s V is reported as a measure of effect size. According to conventional thresholds, V ≈ 0.10 indicates a small association, V ≈ 0.30 a moderate association, and V ≥ 0.50 a strong association.

The summarized results show that the statistically significant relationships are fundamental to the theoretical and empirical scope of the study. The most pronounced is the relationship between the effectiveness of administrative communication and the perceived consistency of subsequent control, which confirms the role of vertical coordination as an important mechanism for transforming centralized European requirements into operational reality. In contrast, the relationship between clear internal rules and perceived differences in the implementation of control is weaker, suggesting that the formalization of a regulatory framework does not guarantee harmonization. The conclusion is similar: coordination between Member States and communication between the customs administration and businesses have a moderately pronounced influence, indicating their supporting and structurally determining functions in building operational security.

From a management perspective, the distribution of the correlation between organizational and communication factors averages the potential for harmonization. In the context of Europeanization, this means that convergence is not an automatic result of regulatory unification but depends on administrative capacity for internal adaptation and the implementation of common standards through sustainable communication mechanisms. The moderate strength of the relationship between communication and the consistency of control suggests that institutional preparation and coordination can serve as “stable levers” to enhance the effectiveness of the reform. At the same time, the lower coefficients in the remaining dependencies highlight the conditional nature of harmonization in an environment with varying digital preparedness and resource availability. The long-term effect of the reform on post-clearance control will depend on targeted investments in the management of customs institutions, the digital competence of customs authorities, and institutional trust between levels of government.

5. Discussion

The findings are considered in relation to the main hypothesis (H₁) formulated in the introduction: first, to what extent is the new EU customs reform expected to contribute to greater procedural consistency and effectiveness of customs post-clearance control within the EU and in Bulgaria (H_1a); second, what practical and organizational challenges may the Bulgarian customs administration face when implementing post-clearance control under the new EU customs reform (H_1b); and third, which specific practical difficulties in the Bulgarian context may limit or offset the expected positive effects of the reform (H_1c). The results should be interpreted within the framework of the evidence based on the expert opinions of the respondents, reflecting the expected institutional dynamics rather than the empirically verified results after the implementation of the reform. The approach to centralizing data management and risk assessment should be implemented in parallel with a redefinition of administrative discretion, a reallocation of coordination responsibilities, and changes in accountability structures between EU-level institutions and national customs administrations. The effectiveness of the reform, therefore, depends not only on digital tools but also on a holistic re-thinking of governance and institutional adaptation in each Member State.

The statistical analysis and the survey data provide strong support for the first sub-hypothesis. The results show that the reform is perceived as a significant opportunity for harmonization, modernization, and improved efficiency in customs control. The established relationship between the effectiveness of internal communication and the uniformity of the applied customs post-clearance control procedures (χ² = 21.992, p < 0.001) indicates that organizational communication is a determining factor in achieving consistent, transparent control procedures. Customs officials who express an opinion on effective vertical communication within the administration demonstrate greater confidence in the uniform application of the rules. The finding confirms the premise that structural coherence and information exchange are prerequisites for harmonization, in line with the theoretical framework of risk-based customs management proposed by Widdowson and Preece (2013) and the principles of administrative coordination highlighted by D’Angelo (2023). The empirical results support the argument that establishing an EU Single Customs Authority and an EU Customs Data Hub will enhance harmonization of procedures across Member States. By centralizing data management and facilitating risk-based selection, the reform will minimize duplication of efforts and inconsistencies in enforcement (European Commission, 2023e). The results align with the fact that integrated data processing enables a shift from paper-based to data-based controls, thereby improving accuracy and efficiency. Furthermore, the statistically significant correlation between intra-EU communication and control coherence (χ² = 6.310, p = 0.012) empirically confirms that harmonization cannot be achieved without increased coordination between Member States. Fragmentation in data exchange, diverse risk assessment methods, and different operational practices have led to uneven implementation of control measures, a weakness repeatedly reported by the European Court of Auditors (2021, 2023).

The survey demonstrates overwhelming optimism among customs officials regarding the digitalization process: 88% of respondents expect that digitalization will streamline customs processing, 85% foresee facilitation of customs formalities, and 75% believe that it will improve the overall efficiency of customs controls. These results confirm the theoretical argument that post-clearance controls, when supported by digital infrastructure and real-time data, become the most effective mechanism for ensuring compliance in globalized supply chains (Clark, 2017). The results thus confirm that the new EU customs reform is expected to accelerate the systematic modernization of post-clearance controls in Bulgaria, improving both the quality of customs procedures and the transparency and accountability of the entire system. The results, addressing the second sub-hypothesis, reveal a parallel set of challenges that must be overcome to realize the full potential of the reform. Customs officials have identified significant concerns regarding administrative capacity, data management, and the preservation of institutional sovereignty. The planned transition from the authorized economic operator (AEO) procedure to the new “Trust and Check” status implies a significant reassessment of existing certificates across the EU and continuous digital surveillance of traders. Significant staff retraining, technical improvements, and inter-institutional coordination are expected to accompany the expectation that real-time surveillance will reduce the need for physical checks. The difficulties reflect the inextricable link between the pace of automation reform implementation and the pace of staff qualification, parallel with the development of digital infrastructure. The analysis highlights that granting customs authorities’ direct electronic access to companies’ internal systems (accounting, ERP, and financial data) introduces new cybersecurity and privacy risks (Ivanov et al., 2024). Ensuring data integrity and maintaining trust between business and administration are essential for the effectiveness of post-clearance controls in a digital environment. The “seamless data exchange” reform may face resistance from the business community due to insufficient data protection mechanisms.

Although the reform aims to achieve harmonization, several respondents highlighted that Member States, such as Bulgaria, face specific geographical and trade challenges that require flexibility at the national level. The observation is consistent with Zhelyazkova et al.’s (2024) argument that the unification of customs risk management should not eliminate individual administrations’ capacity to address unique operational conditions. Effective harmonization, therefore, needs to be complemented by adaptive mechanisms allowing for differentiated implementation within a shared regulatory framework.

The possibilities of Europeanization, multi-level governance, and the aggregation of customs data and risk assessment increase the functional dependence of post-clearance control on institutional connectivity. Harmonization is not automatically achieved through aggregated digital tools but rather manifests itself through effective communication procedures, interoperable systems, and a clear allocation of competences between administrative levels. In addition, differentiated implementation implies that the same tools at the EU level can yield different results when national administrations have different digital capacities and organizational readiness.

Relying on digital technologies and data analytics for the reform requires a significant upskilling of customs officials. The shift from paper-based to electronic post-clearance controls implies that control authorities need to acquire skills in information systems, data interpretation, and risk modeling. The result supports Smason’s (2022) claim that the success of digital verification and AI-based risk analysis depends on both human expertise and technological capabilities.

In the context of the third sub-hypothesis, the survey results identify several interrelated risks. Some respondents express reservations regarding the readiness for direct electronic access to internal business systems, linking this to concerns about data protection and cybersecurity. These attitudes indicate that trust between the administration and business remains a fundamental condition for the effective implementation of the digital model for subsequent customs control. In parallel, the moderate strength of the relationship between coordination and control consistency, as established in the statistical analysis, indicates that digital integration alone does not provide a basis for uniform implementation without robust communication mechanisms in place in advance. Therefore, the expected benefits of “seamless data exchange” may be partially limited if the institutional environment does not provide sufficient protection, transparency, and procedural predictability.

In parallel, the results indicate that human and organizational capacity are among the main practical difficulties in the Bulgarian context. Some participants in the study point to the need for additional qualifications and the adaptation of work processes to the electronic environment, which confirms the relationship between the pace of automation and the pace of increasing expertise. The established relationship between the effectiveness of internal communication and the perceived consistency of control also supports this conclusion. This factor has a significant impact on the transition from organizational coordination to the digitalized model of subsequent customs control. In conclusion, the practical difficulties are not limited to technological limitations but also include human resources, organizational management, and institutional trust. If these aspects are not addressed systematically, there is a risk that some of the expected positive effects of the reform will be realized to a limited extent or with uneven intensity.

By integrating the results of the three sub-hypotheses, the study reveals a dual dynamic: while the reform offers significant opportunities for modernization, it simultaneously imposes high demands on customs administrations to adapt. Statistical relationships identified, especially between communication, consistency, and coordination, highlight that harmonization is not just a procedural outcome but a function of institutional connectivity. Strengthening communication channels across administrative levels, improving cross-border cooperation, and building digital competencies are essential prerequisites for the reform’s success.

These results may provide insights into enriching the theory of customs management. The results support the conceptual shift described by Veenstra and Heijmann (2023) from traditional border inspection to data-driven audit management, where controls are exercised after transactions through continuous digital surveillance. In this way, post-clearance controls become not only a verification mechanism but also a feedback system that informs risk analysis and compliance strategies. In that context, Bulgaria’s experience reflects at the micro-level the impact of the EU’s transition to a single, intelligent customs system. The empirical evidence supports the research hypothesis that the new EU customs reform will be a major driver of the development and modernization of post-clearance controls. The data-driven approach to the reform, supported by institutional centralization and automation, will improve efficiency, transparency, and harmonization of customs operations. However, its success will depend on national administrations’ capacity to adapt, invest in digital skills, and maintain a balance between European integration and local operational autonomy. Addressing these challenges through a phased implementation, targeted capacity building, and strengthened data security protocols will be essential to achieve a functional and sustainable post-clearance control model under the new European customs framework.

6. Conclusions

The study confirms that the new EU customs reform represents a significant transformation in the conceptual and operational framework of customs control and, more specifically, in the functioning of post-clearance controls as a central component of the European customs system. The findings show that the reform will not only change existing procedures but also redefine the logic of controls themselves, moving from transaction-based verification to continuous, data-driven surveillance that relies on integrated digital platforms, unified databases, and intelligent risk management tools.

Empirical evidence collected from customs officers and economic operators in Bulgaria reveals a strong, statistically significant relationship between effective communication, procedural consistency, and the overall effectiveness of post-clearance controls. The study confirms that communication and coordination at administrative levels, as well as between Member States, are critical factors for harmonized customs practices. The introduction of a single EU customs authority and a single customs data center is expected to reduce fragmentation, improve analytical capacity, and ensure uniform application of customs rules across the European Union. These developments are in line with the reform’s ambition to create a simpler, more innovative, and more secure customs environment that is able to meet the demands of global trade and digitalized supply chains. At the same time, the study identifies several structural and operational challenges that need to be addressed to realize the reform’s potential fully. Among the most significant are the resource and organizational pressures associated with the transition to the Trust and Check system, the need for large-scale retraining of customs officers, and the management of cybersecurity risks arising from increased electronic access to business systems. The loss of partial administrative sovereignty due to the centralization of customs functions also poses risks to national adaptability in countries with specific trade dynamics, such as Bulgaria. These challenges highlight that modernization, while technologically driven, depends on human capacity, institutional readiness, and effective policy coordination.

The results support the study’s hypothesis that the new EU customs reform will serve as a key driver of the development, modernization, and harmonization of customs post-clearance control in Bulgaria and across the European Union. The reform, which focuses on digital transformation, risk-based supervision, and centralized data exchange, has the potential to improve transparency, compliance, and operational efficiency. The study highlights that these benefits will only be achieved through a targeted, phased roll-out and continued investment in the digital and analytical competencies of customs administrations.

From a broader perspective, the study highlights that successful implementation of the reform requires a balance between centralization and flexibility, automation and human judgment, and efficiency and data security. Customs post-clearance control is not only a regulatory mechanism but also an essential tool for continuous improvement in customs management. The Bulgarian case provides valuable information on how Member States can adapt to a single European system while preserving their capacity to address specific local challenges. In conclusion, the new EU customs reform represents the next stage of European integration in customs and trade policy. Its effective implementation will determine the extent to which the European Union can maintain a balance between facilitation and control, openness and protection, and national autonomy, and supranational coherence. If implemented with foresight, transparency, and institutional discipline, the reform will not only improve the effectiveness of customs post-clearance control but also strengthen the EU’s position as a model for integrated, innovative, and sustainable customs management in the global economy.