Employee Strengths Mindset and Voice Behavior: The Roles of General Self-Eﬃcacy and Leader–Member Exchange

: The current paper aimed to explore the linkage between employee strengths mindset and voice behavior, and considered the mediating roles of general self-eﬃcacy and leader–member exchange (LMX) in the relationship. We collected data from 556 participants from various Chinese organizations with a multi-wave design. The results of structural equation modelling analysis showed that employee strengths mindset has a positive association with voice behavior, and employee general self-eﬃcacy and LMX, respectively, mediate the relationship between strengths mindset and voice behavior. More importantly, employee general self-eﬃcacy and LMX also simultaneously mediate the relationship between strengths mindset and voice behavior. The current study is the ﬁrst to investigate the employee strengths mindset–voice behavior linkage, and reveals the cognitive and relational mechanisms underlying the strengths mindset and voice behavior relationship.


Introduction
In the current uncertain and complex business environment, to achieve sustainable development, organizations not only depend on decisions that a top management team makes [1] but also on employee proactive behaviors [2]. Employee voice behavior, a concrete form of proactive behaviors [3], involves the extent to which an employee proactively provides suggestions for organization's improvement and change [4]. Employee voice behavior serves as a key role in promoting organizational sustainable development [5] in that employee voice behavior can promote organizational innovation [6]. In addition, substantial research showed that employee voice behavior can also bring out various other positive outcomes such as enhanced procedural fairness [7], creative work involvement [8], and employee thriving [9]. Given that, it is important and meaningful to identify the antecedents to employee voice behavior [10]. Especially in the context of China's highquality development, all types of organizations need employees to take the initiative to make suggestions for the high-quality development of the organization [11]. Thus, exploring how to motivate employees to execute more voice behaviors has significant importance for the high-quality development of Chinese organizations.
Although extant literature has identified the driving forces of employee voice behavior from different perspectives such as leadership [12], work characteristics [13], employee traits [14], and human resource management practices [15], very li le research considered the relationship between a strengths-based approach and employee voice behavior.
Strengths-based approaches aim to promote human optimal functioning by focusing on individuals' strengths [16].
Since strengths-based approaches such as strengths use, strengths-based intervention, and strengths-based leadership were found to have significant positive effect on employees' a itudes, emotions, behaviors, and performance [17][18][19], more and more researchers have begun to a empt to develop more constructs relevant to strengths-based approaches so as to fully unleash the potential of strengths-based approaches in cultivating employees' positive behaviors. Recently, researchers have developed an important new strengths-based approach construct (i.e., strengths mindset) by integrating mindset into strengths-based approaches [20]. Because an individual's mindset plays a crucial role in determining an individual's behaviors, we should devote more a ention toward employee strengths mindset and its effectiveness [21].
Strengths mindset refers to the a itudes or belief that an individual indicates toward his/her own and others' strengths [20]. Although Ding and Liu have confirmed that strengths mindset is conductive to increased positive affect, task performance, and innovative behavior, we have yet to know the association of strengths mindset with voice behavior. In a broad scope, we also found that very li le research has explored whether strengths-based approaches are associated with employee voice behavior. Such a research gap limits us from completely understanding the effectiveness of strengths-based approaches in stimulating voice behavior. Jia et al. [22] have suggested that it is important and meaningful to investigate the influencing factors of voice behavior from the perspective of a strengths-based approach. Therefore, this study aimed to investigate how and why strengths mindset is related to employee voice behavior.
Employees who have a strengths mindset know their own strengths and can proactively capitalize on their strengths at work [20], which implies that they have a greater ability to provide ideas, suggestions, or information about problems. Given that the ability to voice is a proximal antecedent to voice behavior [23], it is reasonable to posit that there is a positive link between strengths mindset and voice behavior. Our first purpose is to test this positive relationship.
Additionally, we also investigated the mediational mechanism behind the relationship between strengths mindset and voice behavior. For one thing, we extrapolated that general self-efficacy mediates the linkage between strengths mindset and voice behavior. Self-efficacy theory suggests that past successful experience can stimulate individuals' general self-efficacy, thereby leading to positive behaviors [24]. Employees with stronger strengths mindsets are always good at utilizing their strengths at work [20], which enables employees to achieve success more easily [25]. Such successful experience contributes to building employees' general self-efficacy, which in turn, motivates employees to execute more voice behaviors [26]. Therefore, a strengths mindset can influence employee voice behavior through general self-efficacy. Our second purpose is to test this argument.
For another, we anticipated that leader-member exchange (LMX) is an important explanation for why strengths mindset can lead to enhanced voice behavior. Employees high in strengths mindset also pay more a ention to others' strengths [20]. For example, strengths mindset employees always appreciate and praise others' strengths. Employees focusing on their leaders' strengths can build a greater relationship with their leaders and derive more benefits from leaders. According to social exchange theory (SET), an employee who receives benefits from his/her leader will do some meaningful things as a reciprocation [27]. Based on this argument, employees with greater LMX are more willing to provide consecutive suggestions to tackle work problems for their leaders [28]. Thus, our third purpose is to examine whether strengths mindset has a positive relationship between voice behavior through LMX.
In sum, we aimed to theorize and test a dual-mediation model regarding strengths mindset and employee voice behavior in the Chinese context. Specifically, we considered general self-efficacy and LMX as mediators. Although strengths-based approaches such as strengths mindset may be more effective for Western countries' employees, Chinese employees have also higher levels of strengths mindset. The work of Ding and Liu [20] showed that the mean of strengths mindset of Chinese employees was 4.15 (five-point Likert scale). Therefore, in the Chinese context, it is necessary and important to investigate the relationship of strengths mindset with voice behavior. Unfortunately, no study considers this issue. The current study has three main theoretical contributions. First, by investigating the relationship between strengths mindset and voice behavior, this study not only enriches research on the effectiveness of strengths mindset, but also offers a novel pathway of understanding the influencing factor of employee voice behavior. This paper is the first to consider the linkage between employee strengths mindset and voice behavior. Second, by revealing the mediational effect of general self-efficacy on the strengths mindset and voice behavior relationship, the paper can make us be er understand the cognitive mechanism underlying the relationship between strengths mindset and voice behavior. Third, this study also considers LMX as a mediator between strengths mindset and voice behavior, which can help us be er understand the relational mechanism underlying the linkage between strengths mindset and voice behavior.
This paper is organized as follows: First, according to extant literature on focal research variables, we developed hypotheses. Second, research methods including data collection and study sample, measures, and data analysis strategy were described. Third, a series of structural equation modelling (SEM) analyses were conducted to examine hypotheses. Finally, we discussed theoretical implications, managerial implications, research limitations, and future research directions.

Strengths Mindset and Voice Behavior
Since mindsets act as crucial roles in determining individuals' a itudes, emotions, and behaviors [29], strengths mindset has increasingly received researchers' a ention in the field of organizational behavior and positive psychology. Strengths mindset includes cognitive and relational components. With respect to the cognitive component, employees high in strengths mindset are adept at using their strengths at work, which will make them have higher levels of positive self-cognition [30]. As for the relational component, strengths mindset employees always can focus on others' strengths in ways such as appreciating, praising, and learning from others' strengths [20], which is beneficial for building be er relationships with others. Previous study has found that strengths mindset has positive predictive value for positive affect and employee performance [20]. Nevertheless, more research is needed to further examine the effectiveness of strengths mindset.
Voice behavior has been confirmed to be beneficial to employees and organizations. For example, Ng and Feldman [31] found that voice behavior has a positive effect on employee performance, and the work of Morrison [10] showed that employees' voice behaviors contribute to high-quality decision making and error correction; there was also evidence indicating that employee voice behavior is positively related to innovative behavior [32]. Given that, a large majority of research explored the antecedents to voice behavior from a variety of perspectives [4]. For example, Ng and Feldman [33] found that idiosyncratic deals could significantly promote employee voice behavior; there was evidence demonstrating that empowerment and organizational commitment were positively related to voice behavior [34]. However, no study investigated whether strengths mindset is associated with voice behavior.
We assume that strengths mindset contributes to enhanced voice behavior. First, by definition, strengths mindset employees can make the most of their strengths at work [20]. Research found that strengths use serves as an important elicitor of organizational commitment [35], job satisfaction [36], and well-being [37]. Since these positive outcomes provide rich nutrients for employee voice behavior [38,39], it is reasonable to believe that strengths mindset has a positive linkage with voice behavior. Second, employees with a high level of strengths mindset can experience stronger positive affect [20]. Positive affect has been found to be able to enhance employee voice behavior in that employees scoring high on positive affect possess more emotional resources which are needed to execute voice behavior [40]. Thus, it is possible to expect that strengths mindset correlates with voice behavior. Third, previous research demonstrated that employees who have be er performance are more inclined to proactively provide valuable suggestions [10]. Given that employees who have higher levels of strengths mindset can achieve higher levels of performance, voice behavior might be ignited by strengths mindset [20]. More importantly, the linkage between strengths mindset and voice behavior can be also elucidated by strengths theory suggesting that individuals focusing on strengths can execute more positive behaviors [41]. Since employees high in strengths mindset always focus on strengths [20] and voice behavior is a type of positive behavior [11], strengths mindset may be positively correlated with voice behavior. In sum, we proposed: Hypothesis 1. Strengths mindset has a positive association with voice behavior.

Mediating Effect of General Self-Efficacy
General self-efficacy represents one's belief in the extent to which he/she has the capabilities to successfully complete various work tasks in a given situation [42]. When employees have greater general self-efficacy, they tend to make plans for the future [43], achieve higher levels of job performance [44], and experience greater positive affect [45], job satisfaction [46], and well-being [47]. Bandura [48] suggests that general self-efficacy is a key antecedent to individual's behaviors. A host of studies found that general selfefficacy could also stimulate employees to execute more proactive behaviors [49], innovative behaviors [50], organizational citizenship behaviors [51], and knowledge-sharing behaviors [52]. More importantly, general self-efficacy has been verified to be beneficial to employee voice behavior in that confident employees have higher levels of autonomous motivation which is conductive to voice behavior [53,54].
Although general self-efficacy is generally treated as a trait-like or stable construct [55,56], recent research has found that general self-efficacy can also be cultivated. For example, the work of Fiori et al. [57] showed that social relations can foster individual's general self-efficacy; Zeng et al. [58] found that post-traumatic growth has a significant and positive effect on general self-efficacy. The study of Ding and Quan [59] revealed that when leaders focus on subordinates' strengths, subordinates' general self-efficacy will be enhanced. Nevertheless, no study considered whether strengths mindset is correlated with general self-efficacy.
We expected that strengths mindset is positively related to general self-efficacy. For one thing, self-efficacy theory suggests that past successful experiences contribute to cultivating an individual's self-efficacy [24]. Employees with a strengths mindset can capitalize on their strengths at work [20], which will make them more ready to complete given work tasks [60]. Such past successful experiences will activate employees' general selfefficacy. For another, positive psychologists consistently believe that strengths use is very effective in boosting individual's general self-efficacy [61]. A wealth of empirical studies have supported this point [62][63][64]. Since strengths use is a core outcome of strengths mindset [65], it is feasible to postulate that strengths mindset can boost employee's general selfefficacy.
More importantly, previous research showed that strengths-based approaches such as strengths-based leadership will motivate employees to perform more positive behaviors through general self-efficacy [59]. That is, strengths mindset as a specific type of strengths-based approach may also enhance employee voice behavior through general self-efficacy, primarily because employees high in strengths mindset are more confident in executing positive behaviors such as voice behavior. Furthermore, strengths theory also provides an important rationale for the mediating role of general self-efficacy in the strengths mindset-voice behavior association. Specifically, strengths theory points out that individuals focusing on their own strengths have higher levels of self-efficacy and then execute more extra-role behaviors [61]. Therefore, based on the above reasoning, we proposed: Hypothesis 2. General self-efficacy serves as a mediator between strengths mindset and voice behavior.

Mediating Effect of LMX
LMX as a core construct of social exchange theory has been defined as "the relationship quality between leader and follower" [66]. Its basic tenet is that leaders will build different types of exchange relationships with their subordinates, and that these relationships' quality determines leaders' and subordinates' behaviors [67]. High-quality LMX represents greater trust, respect, rewards, and support [68]. Social exchange theory suggests that if an individual receive benefits from another individual, the individual will provide benefits as a reciprocation [69]. Researchers have conducted a great deal of research on LMX based on social exchange theory. With respect to the effect of LMX, considerable research has found LMX to be correlated with increased organizational citizenship behaviors [70], job performance [71], organizational commitment [72], and job satisfaction [73], and decreased turnover intention [74], role ambiguity, and role conflict [75]. Importantly, LMX also plays an important role in promoting employee voice behavior in that such behavior can be regarded as a reciprocation to leaders' support and trust that employees receive [76]. Previous empirical research has also verified the positive relationship of LMX with employee voice behavior [77,78].
In addition to researching the effects of LMX, substantial research has also investigated the influencing factors of LMX. A meta-analysis of Dulebohn et al. [75] found that subordinates' characteristics such as competence, agreeableness, and positive affectivity, leadership such as transformational leadership and contingent reward behavior, and interpersonal relationship such as perceived similarity and leader trust are positively associated with LMX. However, li le is known about the relationship between strengths mindset as a crucial subordinate characteristic and LMX. We postulated that strengths mindset has a positive relationship with LMX. For one thing, strengths mindset includes a relational component [20]. When subordinates appreciate, praise, and learn from their leaders' strengths, leaders are more prone to form high-quality exchange relationships with them because leaders believe that they receive more respect and trust from subordinates [79]. For another, strengths mindset can produce more strengths use behaviors [20]. Given that LMX can be enhanced by strengths use behavior [80,81], strengths mindset is positively related to LMX.
According to the above arguments, strengths mindset has a positive association with LMX, and LMX contributes to enhanced voice behavior. Thus, we further believe that strengths mindset will have a positive linkage with voice behavior via LMX. Based on strengths theory, strengths use will improve LMX, which in turn, motivates subordinates to engage more at work as a reciprocation to leaders [81]. Similarly, strengths mindset as a crucial elicitor of strengths use [20] will also improve LMX and then promotes subordinates to execute more voice behaviors. As such, we obtained the following hypothesis:

Hypothesis 3. LMX acts as a mediator between strengths mindset and voice behavior.
The proposed model is displayed in Figure 1.

Data Collection and Study Sample
This study selected Chinese employees from various organizations in China (e.g., IT and energy industries) as samples by convenience sampling method. Such a sampling method has been widely used for survey research design [82]. The reason why we selected employees from various organizations is to extend the generalizability of our results. We recruited 45 MBA students who have a full-time job as our assistants, and requested each of them to invite 20 colleagues at least to join our survey. These MBA students received extra course credit as a reciprocation. We initially interviewed these students to know whether their organizations encourage employees to voice. These students indicated that their organizations or departments have a good climate for voice. A three-wave approach design was adopted to collect data with a time lag of two weeks. Previous research [83] has shown that a two-week interval is enough to reduce potential testing common method bias (CMB). Each participant received a fix code so that we could obtain matched data across three waves. Before collecting data, with respect to how to carry out the survey, we trained research assistants. After obtaining consent, the survey was conducted. We made a promise that the personal information of participants would be viewed as strictly confidential and merely utilized for academic research. Participation was voluntary.
At Wave 1, participants were invited to fill questionnaire including demographic variables and strengths mindset scale. At this phase, we received 783 questionnaires. Two weeks later, we invited participants who responded at Wave 1 completed general selfefficacy and LMX scales. At this wave, a total of 696 questionnaires were received (88.89% response rate). At Wave 3, participants were requested to complete voice behavior scale. A total of 608 participants responded to this survey (87.36% response rate). Finally, we derived 556 matched data. According to suggestion of Thompson (2000), the sample size should be 10-15 times of the number of measurement items (12 strengths mindset items, 10 general self-efficacy items, 7 LMX items, and 10 voice behavior items). Therefore, our sample size is appropriate.
Among them, 51.26% were male, 48.74% were female; 1.62% employees had doctoral degrees, 29.32% employees obtained a master's degree, and 69.06% employees obtained a bachelor's degree or under; employees who did not have any leadership responsibility represented 67.09%, and 32.91% were leaders. In addition, the mean of age was 32.61 (standard deviation = 6.24), and the mean of organizational tenure was 6.41 (standard deviation = 6.03).

Measurement Scales
Because general self-efficacy, LMX, and voice behavior scales were in an Englishbased edition, we obtained these scales' Chinese edition by the "translation and backtranslation" procedure suggested by Brislin [84]. All items of strengths mindset, general self-efficacy, and voice behavior were assessed by 5-point Likert scale ranging from "1 = strongly disagree" to "5 = strongly agree".
Strengths mindset. We adopted 12-item Chinese Strengths Mindset scale developed by Ding and Liu [20] to measure strengths mindset. This scale has showed good discriminant validity, and convergent validity, and reliability. One example item was "I believe that strengths are the greatest area of success". In this study, this scale's Cronbach's α was 0.93.
General self-efficacy. We adopted 10-item scale developed by Scholz et al. [85] to measure general self-efficacy. One example item was "I can always manage to solve difficult problems if I try hard enough". This scale's Cronbach's α was 0.88.
LMX. The 7-item scale used by Van Breukelen et al. [86] was used to measure LMX. An example item was "How well does your supervisor understand your job problems and needs?" (anchors: 1 = not a bit; 5 = a great deal). This scale's Cronbach's α was 0.97.
Voice behavior. We measured voice behavior with a 10-item scale developed by Liang et al. [87]. An example item was "I will take the initiative to speak reasonable suggestions to help achieve the organization goal". This scale's Cronbach's α was 0.95.
Control variables. According to previous research on antecedents to voice behavior [12,88], gender, age, and education may influence employee voice behavior. Thus, we treated the three variables as control variables. Gender and education were coded as follows: "1 = male, 2 = female"; education: "1 = under bachelor's degree, 2 = bachelor degree, 3 = master degree, 4 = doctor degree". We required participants to demonstrate their age in years.

Data Analysis Strategy
To verify our hypotheses, we first conducted descriptive statistic and correlation analyses. Second, confirmatory factor analysis (CFA) was applied to test discriminant validity. Third, an unmeasured common method factor method was used for testing CMB. Third, SEM was utilized to examine Hypotheses 1-3 in that SEM is a more appropriate approach to testing a dual-mediation model [88]. Table 1 reported means, standard deviations, and correlations of research variables. With respect to correlations, strengths mindset positively correlated with general self-efficacy, LMX, and voice behavior; general self-efficacy positively correlated with LMX, and voice behavior; LMX is positively related to voice behavior. These outcomes provide initial evidence for our hypotheses.

Confirmatory Factor Analysis
First, we deployed CFA to test the discriminant validity of strengths mindset, general self-efficacy, LMX, and voice behavior. To decrease inflated measurement errors because of multiple items [89], three random item parcels were created for strengths mindset, two random item parcels for general self-efficacy, and two item parcels for voice behavior based on its two dimensions (i.e., promotive voice and prohibitive voice). Analytical results were displayed in Table 2. The full-factor model concerning the four focal research variables reported an acceptable fit to the data (χ 2 = 122.74, df = 71, χ 2 /df = 1.72, RMSEA = 0.04, CFI = 0.99, TLI = 0.99, IFI = 0.99), and its fit to the data was be er than others' fit to the data.
Second, according to the recommendations of Podsakoff et al. [90], an unmeasured common factor method was employed to examine the data's CMB. We created a common method factor and loaded it on all item parcels of strengths mindset, general self-efficacy, and voice behavior and on all items of LMX. Results showed that the five-factor model did not exhibit a be er fit to the data (χ 2 = 119.72, df = 70, χ 2 /df = 1.71, RMSEA = 0.04, CFI = 0.99, TLI = 0.99, IFI = 0.99) than the four-factor model comprising the focal variables. Therefore, in this study did not exist serious CMB. Notes: a general self-efficacy and LMX merged. b general self-efficacy, LMX, and voice behavior merged. c all variables were merged into one factor.

Hypothesis Testing
SEM with bootstrapping analysis (re-sample 5000) was used to test research hypotheses, and 95% confidence intervals (95% CI) were deployed to evaluate the significance of path coefficients. Hypothesis 1 posited that a strengths mindset is positively associated with voice behavior. To test this hypothesis, we created a SEM without mediator and controlled employees' gender, age, and education (Model 1). This model showed a good fit to the data (χ 2 = 36. Furthermore, we also simultaneously tested the mediational effects of general selfefficacy and LMX on the relationship between strengths mindset and voice behavior. This model fi ed the data very well (χ 2 = 189.47, df = 113, χ 2 /df = 1.68, RMSEA = 0.03, CFI = 0.99, TLI = 0.99, IFI = 0.99). An indirect relationship of strengths mindset with voice behavior via general self-efficacy was significant (estimate = 0.17, 95% CI: [0.06, 0.28], p < 0.001), and an indirect effect of strengths mindset and voice behavior via LMX was significant (estimate = 0.14, 95% CI: [0.06, 0.23], p < 0.01). However, the two indirect effects did not have significant difference (estimate = 0.02, 95% CI: [−0.16, 0.20], p > 0.05).

Conclusions and Discussion
In the context of China's high-quality development, all types of organizations need employees to provide advice for the high-quality development of the organization. To be er stimulate employees to execute more voice behavior, this study investigated whether employee strengths mindset is linked with voice behavior, and considered the mediational effect of general self-efficacy and LMX on this relationship. We found that strengths mindset has a significant predictive value for voice behavior, and general selfefficacy and LMX, respectively, and simultaneously, mediate the association of strengths mindset with voice behavior. This study has several theoretical and practical implications.

Theoretical Implications
This study has several theoretical contributions. First, this study identified a new antecedent to employee voice behavior. We found that employees strengths mindset is conductive to increased voice behavior. This finding is consistent with the logic that strengths mindset employees can experience higher levels of organizational support for strengths use which is associated with increased voice behavior [22]. Although previous research has explored the relationship of growth mindset with voice behavior [91], the present paper is the first to consider the strengths mindset and voice behavior relationship. Ding and Liu [20] pointed out that both strengths mindset and growth mindset are the specific form of personal mindsets. However, growth mindset is distinguished from strengths mindset in that the former points to the belief about whether individuals view their intelligence as changeable [92], whether the la er refers to the a itudes and belief that individuals hold toward their own and others' strengths [20]. Therefore, this study not only extends research on the relationship between personal mindsets and voice behavior, but also provides a new perspective of promoting employee voice behavior.
Second, this study reveals the cognitive mechanism underlying the linkage between strengths mindset and voice behavior. We confirmed the mediational role of general selfefficacy in the linkage between strengths mindset and voice behavior. Specifically, strengths mindset employees are good at taking advantage of their own strengths [20]. Employees who play to strengths at work have higher levels of self-efficacy [61,63], which in turn, motivates employees to carry out more positive and proactive behaviors such as voice behavior [93]. Although previous research has indicated that strengths mindset is able to influence employees' behaviors through positive affect, we have yet to know whether strengths mindset has a positive effect on employees' behavior through cognitive process. Therefore, this study contributes to enriching our understanding of the cognitive process mechanism underlying the strengths mindset and employee behavior linkage by confirming the mediational role of general self-efficacy in this linkage between strengths mindset and voice behavior.
Third, we also found that LMX significantly mediates the association of strengths mindset and voice behavior. According to the definition of strengths mindset, strengths mindset includes a relational component [20]. For example, when employees with a high level of strengths mindset proactively appreciate and praise their leaders' strengths, these leaders will experience greater sense of satisfaction about self-value [94]. Such a sense of satisfaction in turn stimulates leaders to regard strengths mindset employees as insiders, which will improve employees' perception of LMX. Social exchange theory suggests that employees with greater LMX will reciprocate their leaders by executing more voice behavior [95,96]. This study provides a piece of important evidence for relation a ribute of strengths mindset. In addition, the present paper also contributes to a be er understanding of the relational mechanism underlying the association between employee strengths mindset and voice behavior.

Managerial Implications
This study has several practical implications for Chinese organizations aimed at boosting employee voice behavior. First, cultivating employees' strengths mindset is an effective way of enhancing voice behavior. Although strengths mindset like growth mindset is generally treated as a stable personal a ribute, it is also changed by effective intervention strategy [97]. Therefore, to nurture employees' strengths mindset, the employer organizations should design and implement employee strengths mindset intervention. The web-based strengths intervention developed by Harzer and Ruch [98] offers an initial scheme. Second, stimulating employees' self-efficacy is also an avenue for improving voice behavior. Previous research has provided a variety of approaches to fostering self-efficacy. For example, Bandura [99] pointed out that enactive a ainments, vicarious experience, and verbal persuasion can enhance individual's general self-efficacy; Appelbaum and Hare [100] found that helping employees set clear goals contributes to boosted general self-efficacy.
Third, we can also suggest that leaders improve their relations with their subordinates to enhance subordinates' voice behavior. According to the work of Chan and Mak [101], benevolent leadership behaviors are quite effective in cultivating LMX. In addition, workplace fun [102], transformational leadership [103], and servant leadership [104] have been found to be beneficial for improving LMX.

Limitations and Future Research Directions
Several limitations should be noted to be er understand our findings. First, our research data were collected from a single source. Although CMB testing showed that CMB of the data did not pose a serious threat to our results, we encourage researchers to re-test our hypotheses by collecting multi-source data so as to improve the robustness of our findings. In addition, the research design of this study does not allow us to examine the causal relationships between strengths mindset, general self-efficacy, LMX, and voice behavior. Hence, in future research, it is necessary to conduct experimental or longitudinal designs to address this issue. For example, researchers can conduct strengths mindset intervention research to examine the effects of strengths mindset.
Second, previous research has showed that positive affect mediates the effect of strengths mindset [20]. However, this study did not control positive affect as a mediator, which makes us fail to understand whether general self-efficacy and LMX have an incrementally mediating effect on the relationship between strengths mindset and voice behavior. Therefore, future research should control positive affect as a mediator so as to rule out its influence on the mediating effects of general self-efficacy and LMX.
Third, although this study revealed the cognitive and relational mechanisms underlying the relationship between strengths mindset and voice behavior, li le is known about the boundary conditions of the effectiveness of strengths mindset. A great many researchers have pointed out that the expression of employees' traits is contingent to trait-related external contexts such as leadership and human resource practices [105][106][107]. As such, future research should a empt to examine whether strengths-based leadership and strengths-based human resource system contribute to the expression of strengths mindset. Institutional Review Board Statement: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research commi ee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed Consent Statement: Before collecting data, we obtained informed consent from all participants. With respect to this study, participation was voluntary, and we promised that all information about participants was merely employed for academic research and treated as strictly confidential, and that they were able to stop participating in our surveys at any step.

Data Availability Statement:
The data that support the findings of this study are available from FL (liufeng@ppsuc.edu.cn), upon reasonable request.