Exploring the Antecedents of Job Crafting: A Conditional Process Analysis

In this paper we investigate whether the relationship between leader and members (Leader-Member Exchange, LMX), a key element of work organization, constitutes a relevant antecedent for job crafting. We also investigate whether role breadth self-efficacy mediates such relationship. Then, we look at organizational-level policies, and explore whether human resource initiatives aimed at exposing employees to developmental experiences may influence both the direct relation between LMX and job crafting and the above mentioned mediated relation. Results of a conditional process analysis (a mediated moderation model) with a sample of 172 store level workers indicate that LMX has a positive influence on job crafting. Results also show that developmental experiences moderates the positive direct relationship of LMX on most job crafting behaviors. Moreover, we also found that developmental experiences moderate the positive indirect effect of LMX on some job crafting behaviors via role breadth self-efficacy. These direct and indirect effects of LMX are stronger when developmental experiences are lower. Managerial implications and directions for future research are discussed.


Introduction
Literature on job crafting has been described as "an exciting area of research" (Oldham & Hackman, 2010: 470) because of the profound implications that proactivity in the workplace and, more generally, a genuine bottom-up approach to job design may have for individuals and organizations.A significant number of studies show the relevance of proactivity and job crafting in relation to work engagement and performance (Bakker, Tims, & Derks, 2012), creativity and human flourishing (Demerouti, Bakker, & Gevers, 2015), self-efficacy (Van den Heuvel, Demerouti, & Peeters, 2015), work satisfaction and well-being (Tims, Bakker, & Derks, 2013).Thus, it seems necessary to improve our understanding about individual and contextual elements that may influence job crafting behaviors (Berg, Dutton, & Wrzesniewski, 2013).
Our study contributes to such literature by exploring whether Leader-Member Exchange (LMX) directly and / or indirectly influences job crafting behaviors through an increase in workers' role breadth self-efficacy.We also explore the idea that developmental experiences may influence both the direct relation between LMX and job crafting and the relation mediated by role breadth self-efficacy.
In available literature, the relationship between supervisory and job crafting behaviors is considered both crucial and controversial.On the one hand, prominent scholars argue that working "out of the limelight" of management's gaze may multiply the perceived opportunities for Job Crafting (Wrzesniewski & Dutton, 2001).Subsequent contributions, however, argue that supervisors and leaders may have a positive influence on job crafting by allowing more autonomy, shared information and increased dialogue (Tims & Bakker, 2010) (Berg, Grant, & Johnson, 2010), developing competences, skills and self-efficacy (Leana, Appelbaum, & Shevchuk, 2009;Tims, Bakker, & Derks, 2014).Thus, it seems important to test empirically these arguments.By studying the relationship between LMX and job crafting, and role breadth self-efficacy as a mediator, we believe we may shed some light on the above mentioned debate.
Moreover, we included in our model developmental experiences as a moderator of the direct and indirect effects, since Human Resource Management literature and Social Influence theory imply a complex interplay between the role of leaders and the role of organizational initiatives and policies in orienting discretionary behavior (Purcell & Hutchinson, 2007).On the one hand, it is argued that supervisors may have a significant role for a successful implementation of HR practices.Thus, a symbiotic relationship may develop in which both supervisors and organizational practices strengthen each other's ability to influence employees' outcome (Kuvaas & Dysvik, 2010).On the other hand, it is also argued that supportive organizational initiatives (such as providing developmental experiences for the employees) may compensate or even substitute the role of leaders, thereby decreasing the relevance of the latter (Bass, 1985;Podsakoff & MacKenzie, 1994).
The goal of our study is to help clarifying why and how LMX positively influences job crafting behaviors, hence contributing to this literature and also providing useful indications for organizations interested in promoting proactivity and, more specifically, job crafting in the workplace.

The Job Demands-Resources Job Crafting Model
Job crafting (JC) is a form of proactive behavior through which workers redesign their job (Wrzesniewski & Dutton, 2001).A common approach to the empirical study of job crafting is the Job Demands-Resources model (Tims & Bakker, 2010), according to which workers craft their jobs by changing their job resources and demands.
Job resources are physical, psychological, social or organizational job elements that allow pursuing work goals and promoting personal growth.Insufficient resources generate anxiety, stress, lower motivation, disengagement, withdrawal (Bakker & Demerouti, 2007) and prevent employees from goal attainment and personal development (Bakker et al., 2003).On the contrary, sufficient resources decrease depersonalization, emotional exhaustion (Fernet et al., 2013), while increasing satisfaction and motivation (Tims et al., 2013b), work engagement (Hakanen et al., 2008), and the ability to develop further resources (Xanthopoulou et al., 2012).
Job demands, on the other hand, are work features that require sustained physical, cognitive or emotional effort.A distinction between challenging job demands and hindering job demands has been proposed (Lepine et al., 2005).Hindering job demands prevent employees from achieving goals by generating stress and anxiety.Challenging job demands, even when experienced as complex and difficult, provide increased mastery experiences, satisfaction, work engagement excitement, passion and personal development (Bakker & Demerouti, 2007).
According to the Job Demands-Resources job crafting model, we can observe job crafting in terms of one (or more) of four types of proactive behaviors, specifically aimed at: i) increasing structural resources; ii) increasing social resources; iii) increasing new challenging job demands; iv) decreasing hindering job demands.

The Relationship between LMX and Job Crafting
According to Social Exchange Theory (Liden, Sparrowe, & Wayne, 1997) high LMX describes a relation between leader and member characterized by mutual trust and frequent exchanges that go beyond the content of the formal job description.The leader provides the follower with social and emotional support, more autonomy, responsibilities, information and feedback, participation to decision making, while the follower reciprocates with increased effort (Graen & Scandura, 1987).Such reciprocity may trigger initiatives that are not expected or formally prescribed by the organization (Liden & Graen, 1980).It may also lead to increased willingness to accept tasks that are not formally prescribed (Liden et al., 1997).Thus, reciprocity may induce members to seek new challenging job demands that go beyond the formal perimeter of their role.
LMX may discourage job crafting in terms of decreasing hindering job demands.First, this may result from a reciprocity obligation towards the leader, as reducing job demands, however hindering, may be seen by the supervisor as a disappointment.Second, reciprocity may also induce leaders to help employees to face their most difficult demands, thereby reducing workers' need to avoid them (Schriesheim, Neider, Scandura, & Tepper, 1992).Finally, appreciation and emotional support may motivate followers to increase their effort when facing hindering demands (Scott and Bruce, 1994).
At the same time, workers with high LMX may be compelled to craft their job by seeking more resources.First, their awareness of resource availability and accessibility may increase, as resources are made more clearly available by the leader (Liden et al., 1997).Also, mutual trust may convince workers to acquire more feedback and other kinds of support from their leaders.Ashford, Blatt, and Vande Walle (2003) showed that a supervisor can influence individuals' feedback seeking through reducing fears of potential image costs.In addition, recognition of an increased job influence, decision latitude and autonomy should make it easier for workers to change their job demands and resources (Leana et al., 2009;Petrou, Demerouti, Peeters, Schaufeli, & Hetland, 2012;Tims et al., 2013).Finally, high LMX allows workers to improve their learning and mental abilities, and seek proactively new forms of social support (Grant & Ashford, 2008), to access more information, different points of view, new technical skills and competencies (Panari, Guglielmi, Simbula, & Depolo, 2010), to think critically about their wok activities (Scholl, 2001) and, consequently, to identify more opportunities to craft their job (Tims & Bakker, 2010).

The Mediating Effect of Role Breadth Self-Efficacy
Role breadth self-efficacy describes the subjects' perception about their ability to perform a set of tasks that go beyond those strictly required by their formal role (Axtell & Parker, 2003;Parker, 1998;Parker, Williams, & Turner, 2006).Thus, it is similar to self-efficacy (Bandura (1977), but it encapsulates better than generic self-efficacy the idea of proactivity at work (Bindl & Parker, 2010;Parker, 2000;Parker & Collins, 2010;Strauss, Griffin, & Rafferty, 2009).
Here we hypothesize a positive relation between LMX and role breadth self-efficacy for a number of reasons.Available research shows that LMX may increase the perception of different forms of efficacy (Schyns, 2004;Walumbwa et al., 2011).First, LMX may increase role breadth self-efficacy by improving enactive mastery in relation to an enlarged and proactive role (Parker, 1998).Indeed, delegation (Liden et al., 1997) is one of the key elements of LMX (Scandura et al., 1986).Second, LMX may influence role breadth self-efficacy through vicarious experiences and social persuasion.When exchanges and mutual trust between leader and member increase, it is more likely that the leader will become a role model for workers (Walumbwa et al., 2011).Also, opportunities for verbal persuasion and encouragement to tackle and overcome work challenges are more likely to increase (Schyns, 2004).Such exchanges are likely to improve the worker's role breadth self-efficacy not just through the social support that becomes available, but also through an improved awareness of the goals to be achieved and the expectations to be met (Axtell & Parker, 2003;Parker, 1998).
The hypothesized positive effect of role breadth self-efficacy on job crafting is also based on several ideas that are found in available literature.First, workers with higher role breadth self-efficacy will comprehend or build more resourceful work environments (Kohn & Schooler, 1982) and believe they can utilize new resources effectively (Van Wingerden et al., 2015).At the same time, workers with higher role breadth self-efficacy are more likely to seek new challenging job demands because their belief to be able to perform effectively may protect them from the fear of sanctions associated with negative performances in extra-role tasks (Morrison & Phelps, 1999).Individuals with high self-efficacy are more likely to be proactive in order to satisfy their ambitions and to fully utilize their abilities (Wood & Bandura, 1989), even by engaging in more complex activities or more challenging goals.Finally, role breadth self-efficacy may also have an influence on job crafting behaviors such as decreasing hindering job demands thanks to increased persistence and effort spent in the face of obstacles.Social cognitive theory shows that people who doubt their own ability tend to decrease their effort, settle for mediocre solutions or abandon the activity, while those with a strong belief in their capabilities tend to increase their effort (Bandura, Adams, & Beyer, 1977).

The Moderating Effect of Developmental Experiences
Wayne, Shore, and Liden (1997) define developmental experiences as the discretionary initiatives through which organizations support and improve the personal and professional development of the employees, typically (but not exclusively) through various forms of formal and informal training.Developmental experiences may satisfy the need of personal growth by increasing the sense of self-determination, control, impact, meaning and enjoyment at work (Rego, Pina, & Cunha, 2009).Developmental experiences may also trigger a sense of competency, autonomy and effectiveness, stimulate creativity, entrepreneurship and prevent a sense of stagnation and frustration (Kets de Vries, 2001).
Building on these premises, we believe that developmental experiences may create psychological conditions that are very relevant for job crafting.Workers tend to reciprocate the attention received from the organization by increasing their effort and dedication (Eisenberger, Huntington, Hutchison, & Sowa, 1986), because of a personification process (Levinson, 1965) which leads them to attribute traits and qualities to organizations and reciprocate initiatives that are beneficial for them (Wayne et al., 1997).
Thus, the obligation to reciprocate generated by a higher level of developmental experiences may explain why employees increase their proactive behaviors aimed at increasing their challenging job demands.For the same reason, they may be more likely to avoid decreasing their hindering job demands.At the same time, the climate of trust and openness perceived by employees in organizations making significant investments in their development may facilitate initiatives aimed at acquiring new structural and social job resources.Also, similarly to what happens when high LMX is present, developmental experiences may help employees to have a clearer understanding of job requirements and, more generally, of the work environment as a whole.

Participants and Procedures
Our study was conducted in a major Italian retail company with the voluntary participation of store-level workers.Although these workers operate in different store aisles and departments, their tasks are identical, e.g., merchandising, re-stocking and customer assistance.Indeed, the company considers their formal organizational position as being the same.Additionally, they receive the same training and have the same work contracts.After agreeing with the Human Resources Director about the methodology, the goals and the content of the study, we delivered 250 questionnaires together with a cover letter in which we summarized the goals of the study and reassured the potential participants about the anonymity of their responses.We provided a box in which respondents were asked to put their filled questionnaire.After about 3 weeks we collected 172 questionnaires correctly filled (69% response rate).The average age of respondents was 40.7 years old (SD = 11.66), the minimum 19 and maximum 66; 55% percent were male.The average job tenure was 10.26 years (SD = 9.30).About 14% of respondents have a bachelor degree or more, 70.9% a high school diploma, 15.1% a middle school diploma or less.

Measures
The measuring scales were translated in the local language (Italian).We utilized a professional translator.To validate the translation, we used the back translation method (Brislin et al., 1973).
Leader member exchange (LMX).In order to measure LMX we utilized Scandura and Graen's (1984) LMX-7 scale.The scale was anchored on a 7-point format ranging from 1 (=strongly disagree) to 7 (= strongly agree).A sample item is the following: "I have an effective working relationship with my supervisor".Cronbach's alpha for this study was 0.98.
Role-breadth self-efficacy.Role breadth self-efficacy was measured through the 10-item scale proposed by Parker (1998).Employees were asked how confident they would feel about carrying out a set of tasks beyond their formal job, for example analyzing a long-term problem to find a solution.The response scale ranged from 1 (= not at all confident) to 5 (= very confident).Cronbach's alpha for this study was 0.95.Developmental experiences.We measured developmental experiences through the 4-item developed by Wayne et al. (1997).A sample item is the following: "In the positions that I have held in this company, I have often been assigned projects that have enabled me to develop and strengthen new skills".The range of responses varied from 1 (=strongly disagree) to 7 (= strongly agree).Cronbach's alpha for this study was 0.92.Job Crafting.We measured increasing structural job resources and increasing social job resources, increasing challenging job demands and decreasing hindering job demands through the sub-dimensions of the job crafting scale developed by Tims et al. (2012).Increasing structural job resources, increasing social job resources, increasing challenging job demands include 5 items each, while decreasing hindering job demands utilizes 6 items.Sample items for each variable are the following: "I try to develop my capabilities" for increasing structural job resources; "I ask colleagues for advice" for increasing social job resources; "When an interesting project comes along, I offer myself proactively as project co-worker" for increasing challenging job demands; "I make sure that my work is mentally less intense" for decreasing hindering job demands.The range of responses varied from 1 (= never) to 5 (= very often).Cronbach's alpha estimates for these scales were, respectively, 0.84, 0.91, 0.94, 0.92.Control variables.We controlled for several potentially relevant variables.First, we controlled for job tenure (number of years in the same job) because, according to Berg et al. (2010b), job experience may influence job crafting behaviors in a variety of ways.On the one hand, long tenured employees may be less inclined to craft their job because they are more accustomed to their tasks.On the other hand, longer-tenured members may have a better understanding of available opportunities for job crafting thanks to a deeper knowledge of their job or the organizational context.
We also controlled for age and gender since both may influence employees' preferences for certain work characteristics (Bipp, 2010) and, by consequence, their motivation for job crafting.
Moreover, we controlled for education, as seen in in other studies (Tims et al., 2012), because higher education may facilitate job crafting initiatives in several ways.First, because education may provide more knowledge and other resources, but also because highly educated employees usually occupy higher level roles, characterized by more autonomy and responsibility, which may allow for more job crafting opportunities (Bakker et al., 2012).For the same reasons we also controlled for formal position.We distinguished between three formal levels: a low level, which includes workers with production duties; an intermediate level, including direct supervisors with administrative duties, and a managerial level.According to Berg et al. (2010a), at different ranks, employees may enjoy different degrees of autonomy or freedom to act as job crafters.

Results
We tested the hypothesized direct effect and first-stage moderated-mediation model using the SPSS version of the PROCESS macro (Hayes, 2013), which generates bias-corrected 95% confidence intervals for making statistical inference.
More specifically, we used the Hayes (2012) SPSS PROCESS macro Model 8. We tested four models 8 with LMX as the independent variable (X), developmental experiences as the moderator (W) and role breadth self-efficacy as the mediator (M) and (respectively) increasing structural job resources, increasing social job resources, increasing challenging job demands and decreasing hindering job demands as outcome (Y).We used age, gender, tenure and education as covariates that simultaneously predicts both the mediator and outcome.
A point estimate was considered significant when it did not include 0 between the upper (ULCI) and the lower (LLCI) bound of the 95% bootstrap confidence intervals.Bootstrap confidence intervals were constructed using 5000 resamples.One of the advantages of the bootstrapping procedure is that the bootstrap confidence intervals respect in a better way the irregularity of the sampling distribution, hence allowing more accurate inferences.
Direct and indirect effects of LMX on job crafting at high and low levels of developmental experiences are shown in table 3.
When employees have a lower level of developmental experiences, LMX has a direct (b = 0.16, p < 0.001) and indirect effect on increasing structural job resources via role breadth self-efficacy (b = 0.03, 95% bias-corrected CI [0.01, 0.10]).
When employees have a higher level of developmental experiences, LMX did not have a direct (b = 0.01, ns) or indirect effects on increasing structural job resources via role breadth self-efficacy (b = 0.01, 95% bias-corrected CI [-0.01, 0.02]).
When employees have a lower developmental experiences, LMX has a direct effect on increasing social job resources (b = 0.18, p < 0.001) but does not have an indirect effect on increasing social job resources via role breadth self-efficacy (b = -0.01,95% bias-corrected CI [-0.04, 0.04]).
When employees have a higher developmental experiences, LMX does not have a direct (b = 0.02, ns) or indirect effect on increasing social job resources via role breadth self-efficacy (b = 0.01, 95% bias-corrected CI [-0.01, 0.01]).
Thus, H1b is supported, while H2b is not supported.

Theoretical Implications
Our results show, first of all, that LMX plays an important role in promoting job crating.While a low LMX may actually generate conformity and discourage job crating, a high quality LMX, based on mutual exchange, trust and support, may actually have an opposite, positive effect.This result is consistent to what was found by Leana et al. (2009) about the positive role that a supportive supervision plays in encouraging job crating.This is also generally consistent with evidence found by Hornung, Rousseau, Glaser, Angerer, and Weigl (2010) about how LMX may facilitate a process of negotiated re-definition of job characteristics (i.e. task i-deal).While we agree that LMX may lead to a more flexible or expandable zones of acceptance that workers and their role senders develop in relation to job activities and performance, our results show that such processes do not necessarily derive from negotiated agreements.In more general terms, our study seems to suggest that high LMX may enable processes of bottom-up job redesign that are quite different from the traditional top-down approach (Oldham & Hackman, 2010).
Second, our results show that, contrary to what we expected, a high LMX does not decrease job crafting behaviors aimed at decreasing hindering demands.This might be explained by two opposing phenomena.On the one hand, high LMX provides resources and motivation that allow workers to better tackle hindering demands.
On the other hand, a relationship based on trust and support may decrease the psychological risk associated with behaviors aimed at decreasing job demands (Morrison & Phelps, 1999;Parker, Bindl, & Strauss, 2010;Vardaman, Gondo, & Allen, 2012).If both phenomena are true, the overall effect of LMX might be non significant.
A third result concerns the role of role breadth self-efficacy.We found that psycological processes related to the relationship between employees and supervisors are significant in explaining job crafting behaviors.High LMX may indeed provide the employees with the material and psycological resources that will improve their sense of self-efficacy, with positive consequences on their propensity to craft their job.Interestingly, though, we did not find that role breadth self-efficacy mediates the relationship between LMX and job crafting behaviors aimed at increasing social resources.This may be explained if we consider that social resources concern advice, help and feedback from the supervisor and / or colleagues (Tims & Bakker, 2010).Literature on feedback seeking (Ashford et al., 2003) and help seeking (Lee, 1997) show that these types of behaviors imply a social cost.For this reason, employees may want to limit the amount of social resources they seek even when they are easily available, as such behavior may signal incompetence and generate dependence (Lee, 1997).Thus, employees with high role breadth self-efficacy may feel compelled to count more on their own abilities and less on seeking social resources, in order to avoid such social costs.As a consequence, this phenomenon might compensate our original argument about the positive effect of role breadth self-efficacy on job crafting, resulting in a non-significant total effect.
We also explored the moderating effect of developmental experiences on the direct and indirect relationship between LMX and job crafting.Similarly to what was found in previous studies, supportive supervision and HR practices are both crucial in encouraging employees' discretional behavior (Kuvaas & Dysvik, 2010;Purcell & Hutchinson, 2007).However, our results show that high LMX and high developmental experiences generate similar effects on employees' role breadth self-efficacy and as antecedents of job crafting, hence they tend to act as substitutes.Such effect appears to be consistent to what other empirical studies found (Maertz, Griffeth, Campbell, & Allen, 2007) and to classic substitute for leadership theory (Kerr & Jermier, 1978).We verified the substitute effect further by following the recommendation by Dionne, Yammarino, Howell, and Villa (2005).We found for role breadth self-efficacy and for each job crafting behavior positively associated to LMX the existence of 5 conditions: (i) a leadership main effect model, (ii) a substitute main effect model, (iii) a joint effects model, (iv) a mediation model, where the substitute mediates the relation between leadership and outcome, and (v) the moderation effect.This result outlines a twofold contribution that our paper provides to both leadership and job crafting literatures.First, our findings enrich the reflection on the relationship between leadership and job crafting.Second, our findings provide further support for the traditional, but still debated substitutes for leadership theory.

Practical Implications
It seems increasingly important to understand how to promote job crafting in organizations facing complex environments and markets.Our study shows some of the tools and initiatives that organizations may effectively use to do it.First, supervisors' ability to establish a high quality relationship with their followers seems crucial to facilitate job crafting.Thus, organizations should develop leadership skills and, more specifically, they should encourage their leaders and supervisors to utilize dialogue, information exchanges, reciprocity, openness, support, role modeling, delegation of responsibilities and autonomy.Systematic literature reviews show that training supervisors in these behaviors is an effective way to increase LMX quality (Dulebohn, Bommer, Liden, Brouer, & Ferris, 2011).Examples of such initiatives are work-related interactions aimed at encouraging seniors to coach, guide, and mentor subordinates (Bhal, Gulati, & Ansari, 2009), programs that help supervisors to learn skills associated with supportive work behaviors, as well as meetings and other opportunities to increase exchanges (Restubog, Bordia, & Bordia, 2009).
According to Walumbwa, Cropanzano, & Goldman (2011: 764) "no firm can guarantee high-quality LMX 100% of the time".Thus, organizations interested in facilitating job crafting should also implement additional initiatives that may complement high LMX, such as providing developmental experiences to their employees.Indeed, our findings suggest that organizations should provide developmental experiences especially to those employees that are not in a position to benefit from the resources and support provided by supervisors.At the same time, when the organizations provide developmental experiences to its employees, supervisors may use their time to take better care of their relationship with those workers who have less opportunities to improve their skills and abilities through such developmental initiatives.

Limitations and Future Research Directions
The main limitation of our study concerns its cross-sectional nature.Thus, we cannot be certain of the causal direction of the tested relations.We built our model based on available theories and evidence, but alternative interpretations may be proposed.Future research could adopt a longitudinal approach to verify the causality of relations.
Second, data on the all variables in our study were based on self-reports, and this may imply the possibility of common-method variance.However, common-method variance has been suggested to be less of an issue in moderated regression (Pierce, Gardner, Dunham, & Cummings, 1993).Also, the guarantee of anonymity to respondents has probably alleviated the common-method bias.Regardless, extending the study over time and establishing a time lag between measures of independent and dependent variables might further decrease the common-method variance bias.Also, utilizing measures coming from multiple sources would have been desirable.
Third, in this study we utilized data gathered within a single organization from workers in the same formal position.Thus, we suggest caution in generalizing our results and, at the same time, we hope that other scholars will replicate our study in other organizations.
Fourth, we focused on role breadth self-efficacy as a mediating variable between LMX and job crafting.
However, there may be many other relevant mediating variables.Leadership is still significantly under-explored in job crafting literature.Autonomy, empowerment, participation to decision making, job satisfaction, trust, are just a few examples, among many, of variables that may play a relevant role in mediating LMX and job crafting.
Similar considerations should be relevant about contextual variables.In our study we focused on developmental experiences, but several other human resource management practices and policies may substitute or neutralize the effect of leadership on job crafting.For example, job design practices such as job enrichment might have a similar effect.Similarly, psychological and personal variables might also play a relevant role.For example, work and motivational orientations might be important in supporting job crafting behaviors (Berg et al., 2010) by intrinsically motivating workers.These are just a few examples of a vast number of interesting research hypotheses that could be tested in future studies.

Table 1 .
Means, standard deviations, and correlations among all study variables

Table 2 .
Regression results of process Note. n = 172.Table values are path estimates from the estimated model.Entries are unstandardized coefficient estimates.LMX: Leader-member exchange; RBSE: Role Breadth Self-Efficacy; DEV: Developmental Experiences; RBSE: Role Breadth Self-Efficacy; ISTJR: Increasing Structural Job Resources; ISOJR: Increasing Social Job Resources; ICJD: Increasing Challenging Job Demands; DHJD: Decreasing Hindering Job Demands.

Table 3 .
Direct and indirect effects of LMX on Increasing Structural Job Resources, Increasing Social Job Resources, Increasing Challenging Job Demands and Decreasing Hindering Job Demands at high and low levels of Developmental Experiences