Organizational Justice and Employee Voluntary Absenteeism in Public Sector Organizations: Disentangling the Moderating Roles of Work Motivation

: Although the relationships between fair treatment by the organization and work-related outcomes are contingent on motivational traits, little scholarly attention has been paid to how extrinsic and intrinsic work motivation shape the inﬂuence of organizational justice on employee voluntary absence in the ﬁeld of public management. In this context, our study aims to explore the direct effect of organizational justice on voluntary absence based on social exchange theory, as well as the moderating roles of extrinsic and intrinsic work motivation in the relationship, building on the equity sensitivity theory. Using National Administrative Studies Project–III (NASP III) survey data from a sample of 709 public employees from two state governments (i.e., Georgia and Illinois) in the U.S. and negative binomial regression models, we found that organizational justice is positively associated with employee voluntary absence. Further analysis showed that while extrinsic work motivation mitigates the positive relationship between organizational justice and voluntary absence, intrinsic work motivation enhances the positive relationship between organizational justice and voluntary absence. Accordingly, our study offers meaningful implications that are essential for public management scholars and organizations to consider in order to develop effective managerial practices based on the ﬁtness between organizational justice and employees’ motivational traits, thus reducing employee voluntary absence and improving organizational performance and sustainability.


Introduction
Absenteeism, which is defined as temporary and unplanned non-attendance at the workplace for any reason [1], has been a key concern in public management over the past decade [2,3].This interest has primarily been driven by the necessity to understand what causes employee absenteeism in order to prevent the associated negative work-related outcomes for public organizations [4].For example, previous empirical studies have demonstrated that various organizational factors, including leadership style, job satisfaction [5], employee age and tenure [6], and performance work system [7], are significant predictors of employee absenteeism.More importantly, some meta-analysis studies have reported that absenteeism results in reduced organizational performance and high employee turnover [8,9].
Despite growing scholarly attention devoted to preventing employee absence in the context of public organizations [2][3][4]10,11], remarkably little empirical research has examined how organizational justice-employee perceptions of the fairness of treatment by the organization-shapes employee voluntary absence.Although absence is divided into two forms, namely voluntary (e.g., unauthorized sick leave or vacation) and involuntary (e.g., illness and not shirking) [12], most previous studies have focused on involuntary absence rates [13][14][15].Considering that voluntary absence is more likely to cause negative organizational consequences than involuntary absence [16], it is essential to investigate the impact of organizational justice on employee voluntary absence in order to improve organizational sustainability.Therefore, we explore the relationship between organizational justice and employee voluntary absence based on the social exchange theory.According to the theory, employees feel a sense of obligation to repay those who show favorable treatment [17].Given that employees perceive fair treatment from their organization or managers as a benefit that they reciprocate with positive work behaviors, the tenet of social exchange can be applied to anticipate the psychological process underlying how organizational justice increases employee attendance [18].Because fair treatment in terms of outcome distributions and administrative procedures represents the extent to which organizations and managers value their employees' work efforts [17,18], we predict that employees with organizational justice are less likely to be absent from work.
However, organizational justice does not exist independently in a vacuum but, instead, interacts with various personal traits to shape work-related behaviors [19].Of particular interest is how equity sensitivity as a significant boundary condition moderates the effect of organizational justice on employee voluntary absence in that employees can differ in their responses to equity or inequity [20,21].Specifically, the equity sensitivity theory suggests that employees generally accept an unfavorable (benevolent with strong intrinsic work motivation), equal (equity sensitivity), or favorable (entitled with strong extrinsic work motivation) input/outcome ratio [20].Based on this theory, we expect that entitled employees who are strongly and extrinsically motivated are likely to be committed to their tasks and stay in the workplace during working hours because they are willing to reciprocate fair treatment by the organization with regard to economic reward distribution [22].Conversely, we anticipate benevolent employees to not reciprocate organizational justice with reduced absenteeism because they are more interested in the internal aspects of the work itself, such as meaningful and challenging work, a sense of accomplishment, and personal development [22].Consequently, extrinsic work motivation might enhance the negative relationship between organizational justice and voluntary absence, whereas intrinsic work motivation alleviates the negative relationship [21].
Surprisingly, unlike in the field of business management, there are few empirical studies that synthesize social exchange and equity sensitivity theories to examine how organizational justice shapes voluntary absence, as well as to explore the moderating roles of extrinsic and intrinsic work motivation in the field of public management [23].That is, understanding the relationship between organizational justice and voluntary absence still poses a major challenge to public management scholars and practitioners [3,10].In addition, considering the different working contexts between public and private sector organizations [24], it is still unclear whether some evidence of the organizational justice-voluntary absence link and the moderating role of equity sensitivity in business management is applicable to public management.In order to fill this gap, we seek to answer the following two research questions: Research question 1: Does organizational justice have a negative relationship with employee voluntary absence in public sector organizations?
Research question 2: Do extrinsic and intrinsic work motivation moderate the negative relationship between organizational justice and employee voluntary absence in public sector organizations?
By doing so, our study advances the understanding of the key role of organizational justice in reducing voluntary absenteeism, which is harmful to organizational performance, by analyzing data collected from two state governments (Georgia and Illinois) in the U.S. Specifically, we provide public management scholars and practitioners with meaningful insight into the dynamics of organizational justice and equity sensitivity derived from the two types of employee work motivation, which could help them effectively manage voluntary absence in public sector organizations.
In the following section, we review the relevant literature and the theoretical perspectives supporting our hypotheses.Subsequently, the data and study variables used for the empirical models are outlined, and the results are explained in detail.Finally, we conclude with an assessment of the implications of the findings for public managers and organizations.

The Impact of Organizational Justice on Employee Voluntary Absence
The early organizational justice literature offers two approaches to conceptualizing organizational justice: (1) distributive justice (concerned with the distribution of outcomes such as pay, promotion, and job security) and (2) procedural justice (concerned with organizational decisions about how extrinsic rewards are determined) ( [25], p. 10).Building on Adams' equity theory, a content approach describes how employees compare their ratio of inputs (i.e., work effort, skill, and performance) to their own perceived extrinsic rewards, and they experience feelings of inequity if under-compensated [26].Employees also perceive their situation as inequitable if their rewards differ from those of others, especially when others' inputs are similar to their own [27].When employees perceive distributive injustice, they are likely to adjust the ratio of inputs to achieve what they see as an input-outcome balance that restores the perceived equity or justice in the distribution of extrinsic rewards [26].
Similarly, in addition to distributive justice, procedural justice involves the cognitive process by which employees judge distributive outcomes [28].Specifically, if employees consider the procedure for determining the distribution of extrinsic rewards to be based on the level of contribution or performance, they are more likely to experience a high degree of organizational justice [25,28].Many justice scholars have emphasized the role of performance appraisal as an especially critical factor in procedural justice effects in organizational settings [29][30][31].For instance, Landy, Barnes, and Murphy [32] demonstrated that the perceived fairness of performance evaluations was highly correlated with the extent to which this procedure was seen to allow employees to express their feelings.If employees believe that extrinsic rewards are distributed regardless of effort and performance, they are likely to perceive a higher degree of organizational injustice [33,34].As a result, the equity theory predicts that employees will correct perceived mismatches between input and reward by lowering performance levels to bring their equity ratio back into balance [25].
The literature on organizational justice in the fields of organizational behavior and human resource management (HRM) has consistently shown that fair treatment is a key predictor of employee work attitudes and behaviors [33,35].In particular, Cohen-Charash and Spector [36], in their meta-analysis of organizational justice research using 190 study samples totaling 64,757 participants, found that employees' perceived justice is a significant predictor of various types of organizational outcomes, such as performance, extra-role and counterproductive work behavior, and employee attitudes.Similarly, in their meta-analytic review of 493 studies conducted between 1975 and 2010, Colquitt et al. [37] also provided evidence that organizational justice is positively related to organizational citizenship behavior and employee task performance, but negatively related to counterproductive work behavior (e.g., sabotage and theft).Since 2010, many public management scholars have explored how organizational justice shapes organizational consequences.Choi [38] reported that fairness perceptions of federal employees in the U.S. were positively associated with job satisfaction and trust in supervisors, but negatively related to an employee's intention to leave.In particular, the study emphasized distributive justice as the strongest predictor of employee work attitudes.In a study of local government employees, Hassan [39] found that both distributive and procedural justice enhance job involvement and organizational identification and attenuate turnover intentions among state employees.More recently, Chordiya [40] found that federal employees who felt a sense of fairness in the distribution of outcomes and procedures for allocating outcomes were less likely to leave their current agency.Surprisingly, although considerable progress has been made, we still lack a comprehensive empirical understanding of the mechanism through which organizational justice influences employee voluntary absenteeism.Voluntary absenteeism is defined as the conscious preference of an employee to perform personal errands or attractive activities instead of their obliged duty on any given day (e.g., vacation or intentionally choosing to be absent due to unnecessary personal reasons, i.e., when employees 'pull a sickie') [41].Given that employees' absences from their regular tasks when they are normally scheduled to work are important predictors of organizational performance [9], it is necessary to examine how organizational justice shapes employee voluntary absenteeism.Specifically, the social exchange theory provides a useful theoretical lens for explaining the relationships between organizational justice and voluntary absenteeism [17,31,42].According to Blau ([43], p. 91), social exchange refers to "voluntary actions of individuals that are motivated by the returns they are expected to bring and typically do in fact bring from others".The core idea of this theory is that individuals will feel obligated to reward those who have benefited them because of the inherent norm of reciprocity in social exchange interactions.That is, employees view fair treatment from their organization or supervisors as a benefit and favor, which deserve reciprocation in the form of positive work-related outcomes [42].This concept of social exchange can be used to anticipate the impact of organizational justice on employee working hours and voluntary absenteeism [37].For instance, when employees are fairly treated by their organization and supervisors, they perceive this exchange relationship as high quality and are, therefore, more likely to repay the fair treatment by reducing voluntary absenteeism.The opposite may also be true.If employees believe they are being treated unfairly in terms of the distribution of rewards by the organization and the process used to make allocation decisions, they will likely judge that the social exchange has been undermined and thus increase voluntary absenteeism.
Indeed, Dittrich and Carrell [44] demonstrated that employees tend to legitimize absenteeism as one available means to respond to low-quality exchange relationships with their organizations caused by unfair treatment.In a similar vein, De Boer et al. [45] found that perceived unfairness at work is a significant predictor of reduced attendance motivation.It is conceivable that psychological stress or illness relating to perceived organizational injustice contributes to this reluctance to attend work, leading to lower levels of input if the employees' work situation remains unchanged.Hashish [46] offered evidence that nurses are less likely to engage in workplace deviance, such as leaving early and poor attendance, when they perceive high levels of organizational justice.Building on these arguments and previous empirical evidence, we propose the following hypothesis: Hypothesis 1. Organizational justice is negatively associated with employee voluntary absence.

The Moderating Effect of Extrinsic and Intrinsic Work Motivation
Beyond equity theory as a rationale for organizational justice, researchers in the fields of organizational behavior and HRM posit that personality traits affect individuals' behavioral reactions to organizational justice, because not everyone responds identically to fair or unfair treatment by the organization in the same contexts [47].That is, the relationship between organizational justice and voluntary absence is contingent on whether employees desire to engage in an activity for external or internal rewards.According to the equity sensitivity theory, employees with high equity sensitivity are more likely to increase their intention to exhibit negative work behaviors against the organization when encountering unfair cues or treatment [20].Conversely, employees with low equity sensitivity have a greater tolerance for situations in which they are unfairly treated by the organization and are thus less likely to engage in counterproductive work behaviors, such as sabotage, lateness, or withdrawal [20].
Huseman et al. [48] identified three types of employees with regard to equity sensitivity to capture individual preferences.First, "benevolents" are those with less sensitivity to the ratio of inputs and outputs and who are less concerned if their inputs exceed their personal rewards [20].In other words, they are willing to do more work in under-rewarded conditions.Benevolent employees as "givers" ( [22], p. 556) are "linked to altruists who derive satisfaction from giving more than they receive or from giving while expecting little or nothing in return" ( [48], p. 321).They are uncomfortable with being on the receiving end of a social exchange and prefer their ratio of outcomes to inputs to be less than that of referent others, and also prefer intrinsic outcomes to extrinsic ones [22].Second, as opposed to benevolents, entitled employees, or "getters" ( [22], p. 556), are individuals who have little sense of obligation or reciprocation, focusing on personal outcomes rather than on giving to others [22].Entitlement-oriented employees are "constantly looking for ways to improve their situation and maximize the rewards given by the organization" ( [49], p. 195) and "tend to place more importance on tangible outcomes" ( [50], p. 446).Finally, there are equity-sensitive employees who fall between benevolent and "entitleds" on the equity sensitivity spectrum.As suggested by the traditional equity theory, they seek to attain an equitable balance in the exchange of inputs and outcomes and will be motivated to relieve the dissonance resulting from unfair treatment by taking action to reduce the inequity.While entitleds and "equity sensitives" display a higher preference for extrinsic tangible rewards (i.e., salary, fringe benefits, recognition of good work, and job security), benevolents show a higher preference for intrinsic outcomes (i.e., performing meaningful work, a feeling of achievement, and a sense of competence) [51,52].
Applying the logic of the equity sensitivity theory to the current study, the effect of organizational justice on employee voluntary absence could differ depending on whether employees are extrinsically or intrinsically motivated.For instance, employees with extrinsic work motivation, such as entitleds, are more likely to invest considerable effort and resources in trying to improve their performance than those with intrinsic work motivation when they are fairly treated by the organization in terms of reward distribution [20,23].That is, entitled employees with high levels of extrinsic work motivation are willing to commit to their jobs and stay at workstations during working hours because they are more inclined to reciprocate fair treatment.In contrast, we would antipcate benevolent employees to not reciprocate higher organizational justice with low voluntary absence since they are more interested in the nature of the job and work, including meaningful and challenging work, a feeling of achievement, and personal worth [20].Specifically, benevolent employees may perceive fair treatment in outcome distribution and decision-making procedures as external controls-contextual conditions supporting the need for performance-contingent rewards-that undermine their preference for internal rewards [23,53].This means that although benevolent employees who are intrinsically motivated feel a strong sense of organizational justice, they are likely to be absent from work because they feel little obligation to reciprocate fair treatment from their organization.
Much of the research on equity sensitivity has examined individual differences in reactions to organizational fairness or unfairness, especially with regard to their potentially moderating impact on work attitudes and behaviors [48].For instance, King, Miles, and Day [54] found that, in identical conditions of under-reward, benevolents reported higher levels of satisfaction than entitleds and equity sensitives.This may be because benevolent individuals are less concerned with the distribution of extrinsic rewards and are therefore more tolerant of situations in which they are under-rewarded [20].Similarly, Kickul and Lester [50] proposed that benevolents' higher threshold of tolerance for unfair treatment may play some part in moderating the negative effects of organizational justice on work attitudes and behavioral outcomes, regardless of the reward situation in the organization.Indeed, their empirical findings indicated that, as perceived fairness increases, equity-sensitive and entitled employees show higher levels of job satisfaction and organizational citizenship behavior than benevolents.Recently, in the context of stateowned manufacturing organizations in China, Han et al. [22] revealed that benevolents in high-quality leader-member exchange relationships are more likely to reciprocate favorable treatment from their supervisors by engaging in higher organizational citizenship behavior (OCB) than entitleds.This result implies that entitled employees who place a higher value on receiving extrinsic rewards are less inclined to reciprocate high leader-member exchange (LMX) with OCB because their LMX emphasizes intrinsic rewards.Based on these arguments and previous empirical evidence, the following hypothesis will be explored: Hypothesis 2. Extrinsic work motivation moderates the negative relationship between organizational justice and voluntary absence such that the relationship is stronger when levels of extrinsic work motivation are greater.Hypothesis 3. Intrinsic work motivation moderates the negative relationship between organizational justice and voluntary absence such that the relationship is weaker when levels of intrinsic work motivation are greater.Based on these arguments and previous empirical evidence, the following hypothesis will be explored: Hypothesis 2. Extrinsic work motivation moderates the negative relationship between organizational justice and voluntary absence such that the relationship is stronger when levels of extrinsic work motivation are greater.Hypothesis 3. Intrinsic work motivation moderates the negative relationship between organizational justice and voluntary absence such that the relationship is weaker when levels of intrinsic work motivation are greater.

Data Collection and Sampling Techniques
In order to test our hypotheses, we used the National Administrative Studies Project III (NASP-III) dataset, a survey of full-time managers from public and nonprofit organizations in Georgia and Illinois.Georgia and Illinois share similar physical areas and have significant urban and rural regions; yet, they have quite diverse cultural, political, and bureaucratic contexts.Georgia is a leader in government human resources reform, including the breakup of civil service and the expansion of at-will employment, while Illinois has strong unions and centralized human resource administration.
NASP III measures managers' work attitudes, behaviors, and career trajectories.The population of public managers in Georgia was developed from the Georgia Department of Audits (DoA) comprehensive list of state employees, whereas the population of public managers in Illinois was developed from a Freedom of Information Act request for a list of all state employees.The survey was administered using letters for Wave I, phone calls and emails for Wave II, and letters for Wave III.The survey, closed in January 2006, included 1849 public managers from 61 governmental agencies in the two states (912 from Georgia and 937 from Illinois) and 1307 nonprofit managers in 305 nonprofit organizations (274 from Georgia and 1033 from Illinois) using the simple random sampling

Data Collection and Sampling Techniques
In order to test our hypotheses, we used the National Administrative Studies Project III (NASP-III) dataset, a survey of full-time managers from public and nonprofit organizations in Georgia and Illinois.Georgia and Illinois share similar physical areas and have significant urban and rural regions; yet, they have quite diverse cultural, political, and bureaucratic contexts.Georgia is a leader in government human resources reform, including the breakup of civil service and the expansion of at-will employment, while Illinois has strong unions and centralized human resource administration.
NASP III measures managers' work attitudes, behaviors, and career trajectories.The population of public managers in Georgia was developed from the Georgia Department of Audits (DoA) comprehensive list of state employees, whereas the population of public managers in Illinois was developed from a Freedom of Information Act request for a list of all state employees.The survey was administered using letters for Wave I, phone calls and emails for Wave II, and letters for Wave III.The survey, closed in January 2006, included 1849 public managers from 61 governmental agencies in the two states (912 from Georgia and 937 from Illinois) and 1307 nonprofit managers in 305 nonprofit organizations (274 from Georgia and 1033 from Illinois) using the simple random sampling method.With 790 respondents, the public sector response rate was 43% (432 from Georgia and 358 from Illinois), while the nonprofit sector total of 430 respondents represented a response rate of 33% (107 from Georgia and 323 from Illinois).The overall response rate was 39% across both sectors.For the empirical analysis of the model examined in the current study, we finally obtained 709 observations because of the inclusion criteria of all variables relevant to our study.

Dependent Variable: Voluntary Absence
Voluntary absence was measured by items such as the following: "Thinking about the last 12 months, please estimate how many days of work you missed because: you took personal leave (e.g., a dentist appointment) and you were not sick or on vacation, but you could not face working".Common measures of employee voluntary absenteeism include frequency and duration [55].This study used absence frequency, which is regarded as a more reliable measure than duration in that it has fewer psychometric shortcomings and is generally considered the best measure of voluntary or culpable absence.

Independent Variable: Organizational Justice
Equity theorists conceptualize "equitable" or "distributively fair" relationships as those in which there is a perceived balance between inputs and personal outcomes [26,34].Indeed, in experimental tests of equity theory, researchers have manipulated equity by leading subjects to believe that they were fairly treated in the distribution of extrinsic rewards.Furthermore, Greenberg [25] viewed the perceived justice of performance appraisals as potentially applicable to procedural fairness.Based on these concepts, several public management researchers have employed a range of identical or similar survey items, encompassing performance evaluations, merit-based promotion and pay, steps taken with poor performers, and decision-making procedures for remunerating good performers [31,38].Therefore, to evaluate respondents' perceptions of organizational justice, four survey items from the existing literature were identified as consistent with the research discussed above: (1) "I feel I am underpaid (reverse-coded)", (2) "Because of the rules here, promotions are based mainly on performance", (3) "Even if a manager is a poor performer, formal rules make it hard to remove him or her from the organization (reverse-coded)", and (4) "The formal pay structures and rules make it hard to reward a good employee with higher pay here (reverse-coded)".These items were scaled from 1 (strongly disagree) to 4 (strongly agree).Cronbach's alpha was 0.70.

Moderating Variables: Extrinsic and Intrinsic Work Motivation
According to Ryan and Deci [56], intrinsic work motivation is defined as the performance of an activity for intangible satisfaction or the enjoyment of the activity itself, while extrinsic work motivation refers to the performance of that activity for tangible outcomes or external rewards.To measure the two types of work motivation, respondents were asked about "what factors (. . . ) motivated you to accept a job at your current organization".First, intrinsic work motivation was constructed from six items:

Control Variables
In addition to the variables described above, several control variables were included in the analysis.Previous studies have reported that employees who are more satisfied with their current job and committed to the organization are less likely to be absent from work [57,58].We measured employee job satisfaction using a single item: "All in all, I am satisfied with my job".In addition, another single item was used to measure organizational commitment: "I feel a sense of pride working for this organization".Both items had a four-point Likert-type response format (1 = strongly disagree, 4 = strongly agree).In addition, although the results were somewhat mixed, the demographic factors of the public and nonprofit managers were identified as important antecedents of hours worked and absenteeism.Among these variables, gender (female = 1) and ethnicity (non-white = 1) were coded as dummy variables.Education levels were coded as categorical variables (less than college = 1, college degree = 2, and graduate degree = 3).We measured the number of children using the following item: "How many (if any) dependent children do you have living in your home?"For state-related measures, the present study used a dummy-coded variable to control for the state context (Georgia = 1).Because the two states differ sufficiently in terms of tax codes and regulations for nonprofit organizations, such differences in context can be expected to affect the work attitudes and behaviors of nonprofit managers.Table 1 summarizes the descriptive statistics for the variables used in the empirical model.

Estimation Technique
Because our dependent variable is a count variable that indicates the incidence rate of an event occurring over a given period of time and therefore shows a Poisson distribution featuring a strong positive skew (see Figure 2), we used negative binomial regression (NBR) models to test our hypotheses.In general, either Poisson regression or NBR is a reasonable method used to test for overdispersion (i.e., the variance of count is much greater than the conditional mean).However, even though the Poisson regression model includes the correct variables, overdispersion may lead to inefficient estimation resulting from standard errors that are biased downward [59].Our goodness-of-fit tests indicated that the alpha parameter, which determines the degree of dispersion, was significantly different from zero.This indicates that there was an overdispersion of the data for voluntary absences of public employees.As a result, the NBR model is preferred to the Poisson regression model, where there is overdispersion.

Results
Table 2 presents the statistical results of the models.First, the results of Model 1 sho that several control variables and moderating variables were significantly associated w the dependent variable.To be specific, both gender ( = 0.191; p < 0.01) and ethnicity = 0.239; p < 0.01) had a positive impact on voluntary absence.One reason might be th female employees take on more family responsibilities than male employees and therefo are more likely to be absent from work.In addition, ethnic minorities may often expe ence more unfavorable treatment from the organization than white employees and th be more likely to stay away from work.Age ( = −0.015;p < 0.01) and state context ( −0.180; p < 0.05) were negatively related to voluntary absence.It may be plausible th younger employees place relatively lower value on their income but higher value on l sure than older employees, thus tending to be absent from work more frequently.Geor state government provides employees with stronger pay-for-performance policies th Illinois state government.Thus, Georgia state government employees are less likely to absent from work than those working in Illinois state government in order to increa their job performance [60].Both organizational commitment ( = −0.107;p < 0.05) a extrinsic work motivation ( = −0.135;p < 0.10) were negatively associated with volunta absence.It is possible that employees who have high levels of emotional attachment their organization are less likely to be absent than those with low levels of organization commitment [58].Finally, state government employees who are highly motivated by ta gible rewards are likely to have fewer absences because they seek to increase their perf mance to receive monetary rewards.
Model 2 shows that organizational justice has a positive impact on voluntary absen

Results
Table 2 presents the statistical results of the models.First, the results of Model 1 show that several control variables and moderating variables were significantly associated with the dependent variable.To be specific, both gender (β = 0.191; p < 0.01) and ethnicity (β = 0.239; p < 0.01) had a positive impact on voluntary absence.One reason might be that female employees take on more family responsibilities than male employees and therefore are more likely to be absent from work.In addition, ethnic minorities may often experience more unfavorable treatment from the organization than white employees and thus be more likely to stay away from work.Age (β = −0.015;p < 0.01) and state context (β = −0.180;p < 0.05) were negatively related to voluntary absence.It may be plausible that younger employees place relatively lower value on their income but higher value on leisure than older employees, thus tending to be absent from work more frequently.Georgia state government provides employees with stronger pay-for-performance policies than Illinois state government.Thus, Georgia state government employees are less likely to be absent from work than those working in Illinois state government in order to increase their job performance [60].Both organizational commitment (β = −0.107;p < 0.05) and extrinsic work motivation (β = −0.135;p < 0.10) were negatively associated with voluntary absence.It is possible that employees who have high levels of emotional attachment to their organization are less likely to be absent than those with low levels of organizational commitment [58].Finally, state government employees who are highly motivated by tangible rewards are likely to have fewer absences because they seek to increase their performance to receive monetary rewards.Model 2 shows that organizational justice has a positive impact on voluntary absence; this does not support Hypothesis 1, which posits that organizational justice is negatively associated with voluntary absence.This result is somewhat surprising and unexpected, because we anticipated that the perceived fairness of rewards that employees receive from the organization serves as an important motivational factor that encourages them not to be absent from work.This counterintuitive finding can be explained by the motivation crowding-out effect theory.According to Perry and Wise [61], public employees generally have stronger intrinsic motivation-characterized by self-sacrifice, attraction to public policy, commitment to the public interest, and compassion towards others-than extrinsic motivation centered on monetary compensation.However, excessive emphasis on organizational justice by offering economic rewards according to employee performance levels may crowd out intrinsic motivation and eventually increase employee voluntary absence [62,63].
We added the interaction terms OJ (organizational justice) × EWM (extrinsic work motivation) and OJ × IWM (intrinsic work motivation) to Model 3 to better understand how the two types of work motivation shape the relationship between organizational justice and voluntary absence.The results show that extrinsic work motivation mitigates the positive effect of organizational justice on voluntary absence, which is consistent with Hypothesis 3. One explanation of this result is that employees with high levels of perceived organizational justice are less likely to be absent from work because they are extrinsically motivated by tangible rewards and are sensitive to justice-related events, which is consistent with the equity sensitivity theory.In contrast, intrinsic work motivation strengthens the positive relationship between organizational justice and voluntary absence, supporting Hypothesis 3. Benevolent employees with high levels of intrinsic work motivation are more likely to exhibit voluntary absence in a work context where the organization treats them fairly in allocating rewards and making decisions in terms of the reward distribution because they have a lower threshold of fairness.
To better understand the nature of the interaction effects pertaining to the two types of work motivation, we visualized how the organizational justice-voluntary absence relationship changes depending on the levels of extrinsic and intrinsic work motivation.Figure 3 shows that, compared to employees who have low extrinsic work motivation (defined as one standard deviation below the mean indicated by the dashed line), employees who have high extrinsic work motivation (defined as one standard deviation above the mean indicated by the solid line) are less likely to engage in voluntary absence.Figure 4 shows that the positive impact of organizational justice on voluntary absence strengthens as intrinsic work motivation increases.lity 2023, 15, x FOR PEER REVIEW supporting Hypothesis 3. Benevolent employees with high levels of intrinsic wor vation are more likely to exhibit voluntary absence in a work context where the org tion treats them fairly in allocating rewards and making decisions in terms of the distribution because they have a lower threshold of fairness.
To better understand the nature of the interaction effects pertaining to the tw of work motivation, we visualized how the organizational justice-voluntary abse lationship changes depending on the levels of extrinsic and intrinsic work moti Figure 3 shows that, compared to employees who have low extrinsic work mot (defined as one standard deviation below the mean indicated by the dashed line), e ees who have high extrinsic work motivation (defined as one standard deviation the mean indicated by the solid line) are less likely to engage in voluntary absence.4 shows that the positive impact of organizational justice on voluntary absence st ens as intrinsic work motivation increases.

Discussion
The purpose of our study was to explore the impact of organizational justice ployee voluntary absence based on the social exchange theory, as well as to test e and intrinsic work motivation as potential moderators in the organizational justi untary absence link based on the equity sensitivity theory in the context of U.S. sta ernment employees.The analysis indicated that organizational justice was positiv sociated with voluntary absence, but this relationship was weaker when employee extrinsically motivated and enhanced when employees were intrinsically motiva the following section, we discuss the important implications of our findings for re and practice.

Theoretical Implications
Despite the recent growth of scholarly interest in the work-related outcome ganization justice [19,29,36,38], few empirical studies have examined how the eq and fair treatment of employees shapes employee voluntary absence.Furthermore that many justice scholars have argued that equity sensitivity is a significant conti factor in the relationship between organizational justice and work-related ou [20, 22,27], there is little quantitative research on how extrinsic and intrinsic work m

Discussion
The purpose of our study was to explore the impact of organizational justice on employee voluntary absence based on the social exchange theory, as well as to test extrinsic and intrinsic work motivation as potential moderators in the organizational justice-voluntary absence link based on the equity sensitivity theory in the context of U.S. state government employees.The analysis indicated that organizational justice was positively associated with voluntary absence, but this relationship was weaker when employees were extrinsically motivated and enhanced when employees were intrinsically motivated.In the following section, we discuss the important implications of our findings for research and practice.

Theoretical Implications
Despite the recent growth of scholarly interest in the work-related outcomes of organization justice [19,29,36,38], few empirical studies have examined how the equitable and fair treatment of employees shapes employee voluntary absence.Furthermore, given that many justice scholars have argued that equity sensitivity is a significant contingency factor in the relationship between organizational justice and work-related outcomes [20,22,27], there is little quantitative research on how extrinsic and intrinsic work motivation, as proxies of the degree of equity preferences, condition the impact of organizational justice on voluntary absence.To fill these research gaps, we investigated the moderating effects of the two types of work motivation on the organizational justice-voluntary absence link by combining the social exchange and equity sensitivity theories, because theoretical integrations are necessary for the effective management of voluntary absence.
First, unlike prior empirical research that has found a negative relationship between organizational justice and voluntary absence [43][44][45], our study revealed that public employees with high levels of organizational justice are more likely to be absent from their work [43][44][45].This is inconsistent with the social exchange theory.The social exchange theory posits that the fair treatment of employees in the distribution of organizational rewards and decision-making leads employees to feel a sense of obligation toward their organization and reciprocate in the form of positive work behaviors [17,42,43].That is, employees with high levels of perceived organizational justice are less likely to be absent from work than those with low levels of perceived organizational justice.Yet, our unexpected findings show that this idea of social exchange theory may not be applicable to public employees.One possible interpretation for this counterintuitive evidence is based on the crowding-out effect theory.According to Perry and Wise ( [58], p. 368), compared to private sector employees, public employees have higher levels of public service motivation (PSM), referring to "an individual's predisposition to respond to motives grounded primarily or uniquely in public institutions and organizations".PSM is a certain personal characteristic of altruistic and prosocial motivation to serve the interests of a community of people, one that might be undermined by organizational justice resulting from performance-contingent rewards [24].Specifically, public employees perceive performance-related practices as external interventions of the organization to control their work behaviors, which in turn reduces their willingness to be committed to pursuing public interest [62,63].This means that organizational justice caused by linking employee performance to rewards puts considerable pressure on public employees with PSM for tangible compensation, which motivates them to engage in voluntary absence.
Another theoretical contribution to the fields of organizational behavior and HRM is that this study advances knowledge regarding how employee work motivation moderates the influence of organizational justice on voluntary absence by combining the social exchange and equity sensitivity theories.Based on the equity sensitivity theory, we anticipated that employees with high levels of extrinsic work motivation-that is, entitleds who are less tolerant of being under-rewarded-would reciprocate high organizational justice with reduced voluntary absence.Our findings show that extrinsic work motivation enhances the positive relationship between organizational justice and voluntary absence, which is consistent with previous empirical studies that identified equity sensitivity as a significant moderator of the impact of organizational justice on various work-related outcomes [22,49,53].It seems that entitled people are more likely to attend work when organizational justice is high [20,22,27].Perhaps entitleds feel that low levels of voluntary absence will be extrinsically rewarded since the organization fairly evaluates their efforts and performance.In addition, the results indicated that employees with high levels of intrinsic work motivation-such as benevolents, who are more tolerant of being under-rewarded than entitleds, and equity sensitives-are less inclined to reciprocate fair treatment from their organization by attending a scheduled work day.These results indicate that employees' equity sensitivity is an important boundary condition for the impact of organizational justice on voluntary absence through employee work motivation.Consequently, we argue that the equity sensitivity theory offers a promising means to better understanding the role of extrinsic and intrinsic work motivation in predicting the relationship between organizational justice and voluntary absence.

Practical Implications
In addition to the theoretical implications, our study contributes to the ongoing debate regarding whether high levels of contingent incentives in the public sector could result in unintended consequences, since tangible rewards may crowd out the altruistic and prosocial motivation of public employees.Some previous studies have provided empirical evidence that crowding out frequently arises when employee job performance is hard to quantify, which is the case with many of the tasks in public sector organizations.Indeed, several scholars have posited that if it is difficult to objectively measure how well tasks are performed, then introducing contingent incentives to increase organizational justice could backfire, as such a compensation system often brings about negative work-related outcomes [62,64].In this respect, our evidence on crowding out suggests that organizational justice focusing on the distribution of economic rewards based on performance levels could lead public employees with PSM to be absent from work.Given this undesirable effect of organizational justice, we suggest that an awareness of the crowding-out perspective encourages public managers and organizations to be more cautious in implementing economic incentives to reduce employee absenteeism.An alternative approach effective in motivating public employees is to execute a job redesign that provides employees with motivational factors such as job autonomy, skill variety, and task significance.For example, discretionary human resource management practices and empowering leadership may be useful to promote public employees' normative public values and motivate them to be committed to serving the public interest.Another potential option may be to grant recognition or awards to public employees who sincerely contribute to organizational performance by using multi-source assessment methods.For example, a 360-degree evaluation tool allows managers to recognize and reward employees who are self-sacrificing in their efforts to attain organizational goals, but who are not properly recognized by performance-related pay practices.It is possible that making award winners' names public on the organization's intranet may boost self-esteem and enhance pride for the public service among these employees [65].
From an equity sensitivity perspective, it is important for public managers to understand individual differences as boundary conditions that moderate the effect of organizational justice on voluntary absence.Although our study showed that organizational justice is positively related to voluntary absence, this result may not be applicable to all types of public organizations.For example, it is easy for quasi-governmental agencies, including the Federal Home Loan Banks and the Federal Reserve System, to objectively measure employee job performance and, therefore, perceived organizational justice is likely to reduce voluntary absence.Given that entitled employees are less likely to have regular work attendance when they receive unfavorable treatment from the organization, these agencies need to design performance-contingent reward structures to satisfy the strong equity preferences of entitled employees who have high extrinsic work motivation.Conversely, public organizations with vague organizational goals and public interest-oriented policies can hire individuals with high intrinsic work motivation because they are not sensitive to being extrinsically under-rewarded, which indicates a low threshold for feeling fairly treated.Moreover, instead of emphasizing contingent incentives, public organizations should provide various managerial practices that allow employees to have autonomy in the workplace and feel a sense of creativity and achievement.These practices, which are oriented towards meeting the needs of intrinsically motivated employees but are not related to organizational justice, might reduce voluntary absenteeism in public organizations where organizational goals are ambiguous and performance measures are subjective.

Limitations and Future Directions
The present study has some methodological limitations that may illuminate directions for future research.First, our findings may not be generalizable to different time periods or to other public organizations in other countries because this study relied on one-year, cross-sectional data drawn from two states (i.e., Georgia and Illinois) in the U.S. Thus, future studies should collect longitudinal data, including data from different government levels (e.g., local and executive branches) and from many other countries.Second, it should be noted that the measures of organizational justice used do not fully reflect the dimensionality of organizational justice.That is, interpersonal justice (interpersonal experiences of treatment by decision-making authorities) and informational justice (transparent communication and accurate information about outcome allocations by decision-making authorities) were not included.Future research could generate more accurate estimates of organizational justice by also measuring these two dimensions of organizational justice.Finally, this study divided work motivation into intrinsic and extrinsic.However, these dimensions are not mutually exclusive, as individuals might be motivated intrinsically and extrinsically at the same time without any conflict [66].Thus, future research should construct more fully specified work motives, such as public value, economic concern, and the working environment, and their dynamic interrelationships with organizational justice.For example, it is possible to explore how extrinsic and intrinsic work motivation moderate the influence of the four dimensions of organizational justice (i.e., distributive, procedural, informational, and interpersonal justice) on employee voluntary absence.Moreover, in terms of leadership styles as potential boundary conditions, transactional leadership focusing on contingent rewards to improve followers' performance and transformational leadership emphasizing followers' commitment to the achievement of organizational goals beyond their own self-interest may differently moderate the associations between organizational justice and voluntary absence.In doing so, we can provide better knowledge about the mechanisms through which organizational justice affects work-related outcomes in various organizational contexts.

Conclusions
Our study provides several contributions to understanding organizational justice and employee absenteeism in the field of public management.First, by exploring the effect of organizational justice on employee voluntary absence, the current study answers the first research question of whether employees' perceived organizational justice plays a crucial role in encouraging their work attendance, which is a form of reciprocation for fair treatment by the organization.Second, incorporating the social exchange and equity sensitivity theories, our study answers the second research question of whether equity sensitivity (benevolents with high levels of intrinsic work motivation vs. entitleds with high levels of extrinsic work motivation) conditions the potential benefits of organizational justice by reducing voluntary absence.Although our findings are somewhat inconsistent with previous research in the field of business management, we offer a refined look at the influence of organizational justice on voluntary absenteeism for public management scholars and practitioners, as well as advanced knowledge of how to manage voluntary absence more effectively by understanding the moderating impact of the two types of work motivation.Finally, more work is needed before our theoretical and managerial implications can be substantiated, but we have significant evidence suggesting that public-service motives may be key correlates, if not predictors, of attitudes towards issues of equity.Considering the unexpected negative relationship between organizational justice and voluntary absence, we could go one step further by broadening the view of performance-contingent incentives in terms of motivating public employees to engage in positive work behaviors that benefit the organization.In other words" we provide additional evidence indicating that PSM could be an important factor worth considering in the process of public service management.Managers can consider distinguishing employees' various public service motives and developing a distinct managerial approach for each that better incorporates how these employees are more likely to perceive their organizational environment and balance their inputs with received outputs.Otherwise, employees with high PSM may be overworked to the point of exhaustion, while those with low PSM may never be adequately challenged to fulfill work responsibilities.More generally, we conclude that PSM must be better understood not only as a construct that potentially delineates public-and private-oriented personnel, but also as a piece of a larger motivational puzzle that involves how we comprehend equity theory in public service.

Figure 1
Figure1visualizes the hypothesized model.First, we investigate the impact of organizational justice on voluntary absence based on the social exchange theory.Then, we examine the moderating effect of extrinsic and intrinsic work motivation on the relationship between organizational justice and voluntary absence.

Figure 1
Figure 1 visualizes the hypothesized model.First, we investigate the impact of organizational justice on voluntary absence based on the social exchange theory.Then, we examine the moderating effect of extrinsic and intrinsic work motivation on the relationship between organizational justice and voluntary absence.

( 1 )
Opportunity for training and career development; (2) The organization's reputation for opportunities for women or minorities; (3) Overall quality and reputation of the organization; (4) Desire for less bureaucratic red tape; (5) Desire for a low-conflict work environment; (6) Desire for increased responsibility; and (7) Ability to serve the public and the public interest.Cronbach's alpha for intrinsic work motivation was 0.69.The measure of extrinsic work motivation was similarly constructed from six items relating to tangible rewards: (1) Opportunity for advancement within the organization's hierarchy; (2) Job security; (3) The organization's pension or retirement plan; (4) Benefits (medical, insurance); (5) Family-friendly policies (i.e., flexible work hours, parental leave); and (6) Salary.Cronbach's alpha for extrinsic work motivation was 0.74.

Figure 3 .
Figure 3. Interaction effect of organizational justice and extrinsic work motivation on volun sence.

Figure 3 .Figure 4 .
Figure 3. Interaction effect of organizational justice and extrinsic work motivation on voluntary absence.

Figure 4 .
Figure 4. Interaction effect of organizational justice and intrinsic work motivation on voluntary absence.

Table 2 .
Results of the negative binomial regression for voluntary absence.