Psychological Capital (PsychCap), as a part of the overall positive organizational behavior, has drawn the attention of researchers because of having unique functional standards and adding long-term value to the individual as well as to the context (Youssef-Morgan & Luthans, 2013). Being a composite construct, it has been found in a strong relationship with desired behavioral, attitudinal, and particularly performance-related results in the organization (Luthans, Youssef, & Avolio, 2015). Consistent researches have found it “positive, measurable, theory as well as research-based, open to betterment as state-like and having desired outcomes. It fulfills rigor and applicability scientific criteria, and stress on effective applications` practical proofs. (Luthans et al., 2015).. Therefore, it is highly imperative to understand the basics of this core construct (Luthans & Avolio, 2014).

Extant literature is replete with conceptual as well as empirical evidence that supports the centrality of PsychCap in behavioral sciences. It is considered as one of the human capital`s key subsets that helps in addressing the company`s human-related problems (Shahnawaz & Jafri, 2009). “Embedding the drivers of PsychCap in the organization not only fosters happy and healthy employees but it can also play a significant role in achieving excellent job satisfaction” (Karpagavalli & Subhashini, 2017) p. 110). Practitioners’ interest in the four elements of psychological capital is pragmatic because each of these components can lead to desirable outcome for organization such as perseverance, belief in one`s own capabilities to be successful in a particular situation, positivity about the present and future, and an employee’s ability to recover from or adjust easily to misfortune or change (Karpagavalli & Subhashini, 2017).

No doubt the importance of PsyCap in the positive organizational behavior (POB) has widely been acclaimed conceptually and empirically, it does not warrant that all organizations would accrue its benefits. Public sector organizations, famous for negative connotations like stagnancy and inefficiency (Goodsell, 2003), and suffering from structural weaknesses (Costantini et al., 2017), which have been dubbed organizations with ‘human capital crisis’(Jacobson, 2011), appear to be out of the spectrum of

benefits attached with it. In countries where the public sector is more dominant, health would definitely be the public-sector domain. Within the health sector, nursing has a distinctive place and is one of its system`s largest components, and playing an indispensable role in the provision of high-quality and consistent aid for patients (Nayeri, Nazari, Salsali, & Ahmadi, 2005). Those who are interested in the provision of quality services in healthcare must be serious about the positive psychology of the persons (nurses) who are entrusted with this task. Different studies have looked at the possibilities of how to improve work engagement (WE) among nurses, we believe that little research has been undertaken to observe WE of nurses in the health sector of Pakistan. Furthermore, we believe that organizational commitment (OC), being a central construct that affects employees' working behavior mediates the relationship of PsychCap toWE. In previous literature`s light, there hardly exists any empirical evidence that looks at such relationships among nurses in Pakistan.

By definition, PsychCap shows human beings` constructive psychological conditions of evolution which are characterized by four dimensions. Hope to represent a positive stimulating condition that depends on synergetic feelings of development (1) agency (energy directed towards a goal) and (2) pathways (goal-oriented planning) (Snyder, Irving, & Anderson, 1991). Self-efficacy is the belief about one`s abilities to organize the motivation, mental resources, and necessary course of action for executing particular actions within a specific circumstance (Stajkovic & Luthans, 1998). Resilience represents one`s capacities of rebounding or bouncing back from adversities, failures, and conflicts or even from constructive events, increased responsibilities, and progress (Luthans, 2002). Optimism shows attributive aspects that explain positive occurrences with regard to personal, pervasive, and permanent causes while negative occurrences as temporary, situation-specific, and external (Seligman, 1998).

Each component of this definition may produce different desired outcomes, however, the whole as a composite construct has been identified as a good predictor of performance and job satisfaction (Youssef?Morgan & Luthans, 2015). Organizations concentrate on a higher level of PsychCap because it depends on personal capacities which peoples induce in their employment. And the qualitative improvement in this capital can have constructive effects on outcomes related to employment. People having PsychCap`s high level have been found more energetic which helps in high achievements in life over a longer period of time, and also employees having PsychCap`s high level have the ability to generate multiple solutions to the problems and respond positively to setbacks (Karpagavalli & Subhashini, 2017). Keeping the centrality of construct the concept has been explained in terms of its explanatory aspects with its high order like optimism, efficiency, hope, and resilience (Luthans et al., 2007); and its constructive traits (personality, self- evaluation, and person-job as well as organization fit).These traits have been found positive predictors of expected behaviors like organizational citizenship and negative predictors of turnover intention, counterproductive behaviors, and organizational cynicism (Avey, Luthans, & Youssef, 2010).

There is a theoretical thread that connects PsychCap`s four components. Individulas have the capacity to positively appraise the work setup, and success` probability based on preserving and motivated effort(Luthans et al. 2007). This is supported by an inner sense of intentionality, control, and agency(Youssef & Luthans, 2013). Those individuals who have the capacity of consistently appraising the chances of success and perceive that these chances are within their reach and control induce a positive outlook and willingness to invest energy and resources in pursuing challenging goals even if there happens to obstacles and setbacks.

It is an area of concern because engaged employees have been found more energetic, well-connected with their assigned tasks and consider themselves to be able to manage their job`s demands (Bakker & Demerouti, 2008). It is occupational health psychology`s emerging concept(Wirtz, Rigotti, Otto, & Loeb, 2017). WE, being part of positive organization behavior (POB), is a state of mind of employees that help them affecting their behavior towards desirable organizational outcomes(Simons & Buitendach, 2013). Their are sufficient evidence that supports that there is a positive association between organizational outcomes and positive engagement with the organization(Donaldson & Ko, 2010). While disengaged employees lack commitment and motivation (May, Gilson, & Harter, 2004).

OC as a construct explains an individual attachment to her/his organization (Shahnawaz & Jafri, 2009). Meyer and Allen (1997), typology of its three components—normative, continuance, and affective commitment has got wide popularity and has been validated across cultures and in diverse organizations. Studies have found an association between PsychCap`s four dimensions and commitment towards the organization (Lyons, Duxbury, & Higgins, 2006). Among the three components, the most researched component is an affective component (Field & Buitendach, 2011)and has been found the strongest and rational regarding desirable organizational outcomes (Simons & Buitendach, 2013; Wasti, 2003).

These are sufficient proof to support the contention that individuals and organizations are both positively affected by WE. Therefore examining WE for the purpose to disclose new methods of enhancing it, can lead to empirical implications for individuals as well as organizations, particularly in the government-related sector.

Research Model and Hypotheses

Based on the extant literature, the researchers in the Pakistani context would propose the validation of the following model and hypotheses.

Psychological Capital (PsychCap), as a part of the overall positive organizational behavior, has drawn the attention of researchers because of having unique functional standards and adding long-term value to the individual as well as to the context (Youssef-Morgan & Luthans, 2013). Being a composite construct, it has been found in a strong relationship with desired behavioral, attitudinal, and particularly performance-related results in the organization (Luthans, Youssef, & Avolio, 2015). Consistent researches have found it “positive, measurable, theory as well as research-based, open to betterment as state-like and having desired outcomes. It fulfills rigor and applicability scientific criteria, and stress on effective applications` practical proofs. (Luthans et al., 2015).. Therefore, it is highly imperative to understand the basics of this core construct (Luthans & Avolio, 2014).

Extant literature is replete with conceptual as well as empirical evidence that supports the centrality of PsychCap in behavioral sciences. It is considered as one of the human capital`s key subsets that helps in addressing the company`s human-related problems (Shahnawaz & Jafri, 2009). “Embedding the drivers of PsychCap in the organization not only fosters happy and healthy employees but it can also play a significant role in achieving excellent job satisfaction” (Karpagavalli & Subhashini, 2017) p. 110). Practitioners’ interest in the four elements of psychological capital is pragmatic because each of these components can lead to desirable outcome for organization such as perseverance, belief in one`s own capabilities to be successful in a particular situation, positivity about the present and future, and an employee’s ability to recover from or adjust easily to misfortune or change (Karpagavalli & Subhashini, 2017).

No doubt the importance of PsyCap in the positive organizational behavior (POB) has widely been acclaimed conceptually and empirically, it does not warrant that all organizations would accrue its benefits. Public sector organizations, famous for negative connotations like stagnancy and inefficiency (Goodsell, 2003), and suffering from structural weaknesses (Costantini et al., 2017), which have been dubbed organizations with ‘human capital crisis’(Jacobson, 2011), appear to be out of the spectrum of

benefits attached with it. In countries where the public sector is more dominant, health would definitely be the public-sector domain. Within the health sector, nursing has a distinctive place and is one of its system`s largest components, and playing an indispensable role in the provision of high-quality and consistent aid for patients (Nayeri, Nazari, Salsali, & Ahmadi, 2005). Those who are interested in the provision of quality services in healthcare must be serious about the positive psychology of the persons (nurses) who are entrusted with this task. Different studies have looked at the possibilities of how to improve work engagement (WE) among nurses, we believe that little research has been undertaken to observe WE of nurses in the health sector of Pakistan. Furthermore, we believe that organizational commitment (OC), being a central construct that affects employees' working behavior mediates the relationship of PsychCap toWE. In previous literature`s light, there hardly exists any empirical evidence that looks at such relationships among nurses in Pakistan.

By definition, PsychCap shows human beings` constructive psychological conditions of evolution which are characterized by four dimensions. Hope to represent a positive stimulating condition that depends on synergetic feelings of development (1) agency (energy directed towards a goal) and (2) pathways (goal-oriented planning) (Snyder, Irving, & Anderson, 1991). Self-efficacy is the belief about one`s abilities to organize the motivation, mental resources, and necessary course of action for executing particular actions within a specific circumstance (Stajkovic & Luthans, 1998). Resilience represents one`s capacities of rebounding or bouncing back from adversities, failures, and conflicts or even from constructive events, increased responsibilities, and progress (Luthans, 2002). Optimism shows attributive aspects that explain positive occurrences with regard to personal, pervasive, and permanent causes while negative occurrences as temporary, situation-specific, and external (Seligman, 1998).

Each component of this definition may produce different desired outcomes, however, the whole as a composite construct has been identified as a good predictor of performance and job satisfaction (Youssef?Morgan & Luthans, 2015). Organizations concentrate on a higher level of PsychCap because it depends on personal capacities which peoples induce in their employment. And the qualitative improvement in this capital can have constructive effects on outcomes related to employment. People having PsychCap`s high level have been found more energetic which helps in high achievements in life over a longer period of time, and also employees having PsychCap`s high level have the ability to generate multiple solutions to the problems and respond positively to setbacks (Karpagavalli & Subhashini, 2017). Keeping the centrality of construct the concept has been explained in terms of its explanatory aspects with its high order like optimism, efficiency, hope, and resilience (Luthans et al., 2007); and its constructive traits (personality, self- evaluation, and person-job as well as organization fit).These traits have been found positive predictors of expected behaviors like organizational citizenship and negative predictors of turnover intention, counterproductive behaviors, and organizational cynicism (Avey, Luthans, & Youssef, 2010).

There is a theoretical thread that connects PsychCap`s four components. Individulas have the capacity to positively appraise the work setup, and success` probability based on preserving and motivated effort(Luthans et al. 2007). This is supported by an inner sense of intentionality, control, and agency(Youssef & Luthans, 2013). Those individuals who have the capacity of consistently appraising the chances of success and perceive that these chances are within their reach and control induce a positive outlook and willingness to invest energy and resources in pursuing challenging goals even if there happens to obstacles and setbacks.

It is an area of concern because engaged employees have been found more energetic, well-connected with their assigned tasks and consider themselves to be able to manage their job`s demands (Bakker & Demerouti, 2008). It is occupational health psychology`s emerging concept(Wirtz, Rigotti, Otto, & Loeb, 2017). WE, being part of positive organization behavior (POB), is a state of mind of employees that help them affecting their behavior towards desirable organizational outcomes(Simons & Buitendach, 2013). Their are sufficient evidence that supports that there is a positive association between organizational outcomes and positive engagement with the organization(Donaldson & Ko, 2010). While disengaged employees lack commitment and motivation (May, Gilson, & Harter, 2004).

OC as a construct explains an individual attachment to her/his organization (Shahnawaz & Jafri, 2009). Meyer and Allen (1997), typology of its three components—normative, continuance, and affective commitment has got wide popularity and has been validated across cultures and in diverse organizations. Studies have found an association between PsychCap`s four dimensions and commitment towards the organization (Lyons, Duxbury, & Higgins, 2006). Among the three components, the most researched component is an affective component (Field & Buitendach, 2011)and has been found the strongest and rational regarding desirable organizational outcomes (Simons & Buitendach, 2013; Wasti, 2003).

These are sufficient proof to support the contention that individuals and organizations are both positively affected by WE. Therefore examining WE for the purpose to disclose new methods of enhancing it, can lead to empirical implications for individuals as well as organizations, particularly in the government-related sector.

Research Model and Hypotheses

Based on the extant literature, the researchers in the Pakistani context would propose the validation of the following model and hypotheses.

This study aims to find out the OC`s role as a mediator between WE and PsychCap. The data was collected from the nurses of three large hospitals of Peshawar. A total of three hundred questionnaires were issued for the collection of data. Among which 226 were responded with the 75% response rate. Because of the extremely busy schedule of the nurses in the hospitals, the convenient sampling technique was adopted. The data was collected from those who were conveniently present.

SPSS 20 and AMOS 18 were used for developing the structural and measurement models for testing the hypotheses and mediation effect.

PsychCap

The PCQ scale devolved by Luthans et al. (2007) was used to measure PsychCap`s four dimensions (optimism, hope, resilience, and self-efficacy). PCQ comprises 24 questions. The scale has six items forPsychCap`s each dimension. The example items are; self-efficacy “I feel confident analyzing a long-term problem to find a solution”, hope “If I should find myself in a jam at work, I could think of many ways to get out of it”, Resilience “I usually manage difficulties one way or another at work”, and optimism “When things are uncertain for me at work, I usually expect the best”.

WE

Based on Kahn (1990) three components model, this study used the 9-item Utrecht WE Scale (UWES-9). It comprises 9 questions, wherein three items were for each WE`s dimension with a five-point Likert-type. Example item of the scale for vigor is (“At my work, I feel bursting with energy”), dedication (“I am proud of the work that I do”) and absorption (“I am immersed in my work”).

OC

The 18 items scale developed by Meyer and Allen (1991) was adopted for this study. This scale has six items for each dimension of OC. Example items are affective “I would be very happy to spend the rest of my career in this organization”, Continuance “Too much of my life would be disrupted if I leave my organization” and normative “This organization deserves my loyalty”.

Analysis

The mean, standard deviation, and Cronbach’s Alfa of the study are given below in Table 1.

PsychCap was the independent variable in this study which is consisted of four dimensions. The first dimension of PsychCap was self-efficacy. The Cronbach’s Alpha for PsychCap ranged from .87 to 90, OC from .88 to .91 and1 WE was ranged from .86 to .89. All these valued showed that the scales had internal consistency.

The correlations between the three variables of this study have been presented in Table 2. The r-value of .775 shows that there exists a strong and positive relationship between PsychCap and OC. The p-value is < 0.01 which further demonstrates that the relationship is significant. A significant and strong positive relationship was also found between WE and PsychCap with (r=.673, p < 0.01). The significant and strong positive association between WE and OC was also revealed as the r value was .717 and the p-value was < .01.

Table 2. Correlation between PsychCap, OC and WE

**. Correlation is significant at the 0.01 level (2-tailed).

Correlations between PsychCap, the three dimensions of WE (vigor, absorption, dedication), and OC`s three dimensions (normative, continuance, and affective) has been presented in Table 3Error! Reference source not found.. WE`s all three dimensions have positive and significant correlated with psych ap; vigor (r=.591), absorption (r=.594), and dedication (r=.626). Similarly, OC`s dimensions also have positive and significant correlated with PsychCap; affective (r=.694), absorption (r=.723), and dedication (r=.713).

Table 3. Correlation between PsychCap and Dimensions of OC and WE

Correlations between OC, PsychCap`s four dimensions (optimism, resilience, hope, and self-efficacy) and WE`s three dimensions (dedication, absorption, and vigor,) has been presented in Table 4Error! Reference source not found.. PsychCap`s our dimensions has positive and significant correlation withOC; optimism (r=.644), hope (r=.645), self-efficacy (r=.725), and resilience (r=.682). WE`s three dimensions also have positive and significant correlation withOC; vigor (r=.614), absorption (r=.658), and dedication (r=.658).

Correlations between WE and PsychCap`s four dimensions (optimism, resilience, hope, and self-efficacy) and OC`s three dimensions (normative, continuance, affective) have been presented in Table 5Error! Reference source not found.. PsychCap`s four dimensions has positive and significant correlation with; optimism (r=.560), resilience (r=.652), hope (r=.537), and self-efficacy (r=.589). OC`s three dimensions also have positive and significant correlation with WE; affective (r=.702), continuance (r=.618), and normative (r=.653).

Table 5. Relationship between WE and Dimensions of PsychCap and OC

Testing mediation through Baron and Kenny Approach

To test mediation through Baron and Kenny (1986) approach, the first step is to check the direct path from independent to dependent. It is, therefore a model that was developed to check PsychCap`s impact on WE. In the first step, model fit indices were checked and they were all in the range of acceptance?²(13, n=226) = 13.956, ?²/Df=1.073, GFI=.983, CFI=.999, and RMSEA=.018.

The direct path from PsychCap to WE was significant and the beta value (?=.76, p < .01) indicates that a strong predictor of WE is PsychCapas it is shown in model 1. It therefore, justifies the first hypothesis H₁ of the study, and the first condition for testing mediation was satisfied.

Direct Path from PsychCap to WE

The second step in testing the mediation through Baron and Kenny (1986) is to check the path from independent to the mediator. In this regard, a second model was developed for checking the PsychCap`s impact on OC. All fit indices of the model were in the required range?2(13, n=226) = 18.134, ?2/Df=1.394, GFI=.979, CFI=.996, RMSEA=.042 and RMR=.016.

The path formPsychCap to OC is significant and the beta value (?=.86, p < .01) shows that OC`s stronger predictor is PsychCap as shown in model 2. It therefore, justifies the second hypothesis H2 of the study and the second condition for testing mediation was also satisfied.

Direct Path from PsychCap to OC

The third step for testing the mediation effect was to check the effect of the mediator on the dependent variable. It is, therefore, a model that was developed for checking OC`s impact on WE as shown in model 3. All the values of model fit were in the required range ?2 (8, n=226) = 18.870, ?2/Df=2.358, GFI=.971, CFI=.989, RMSEA=.078 and RMR=. 030.

OC Error! Reference source not found.had a significant positive impact on WE. The beta value (?=.79) shows that OC is also the strong predictor of WE. It therefore, justifies third hypothesis H3 of the study, and the third condition for testing mediation was also met.

Direct Path from OC to WE

The fourth and last step in testing the mediation effect through Baron and Kenny (1986) is to check the path from independent (predictor) to dependent (criterion) in the presence of a mediator. The new model was therefore developed to check the mediating effect of OC between PsychCap and WE as shown in model 4.All the values of model fit were in the required range ?2(32, n=226) = 47.852, ?2/Df=1.495, GFI=.957, CFI=.991, RMSEA=.047 and RMR=. 027.

The path between WE and PsychCap was still significant in the presence of OC, however, the value of ? was reduced from .76 to .29. As the path between WE and PsychCap was significant and the association was also still present. Therefore it is concluded that OC partially mediated the association between PsychCap and WE among the nurses. Hypothesis H4 was also accepted.

. Indirect Path from PsychCap to WE through OC

The present study investigated OC`s impact as a mediator between WE and PsychCap of the nurses. The results of the studies show that PsychCap is highly related to WE. These results are also similar to the previous studies like Costantini et al. (2017). The study`s results further explain that OC is also related to psychological capital. This result is also in line with the previous work on the association between OC and psychological capital conducted by Lyons et al. (2006), Sinha et al. (2002), and Youssef and Luthans (2007). The relationship between OC and WE were also found, which is similar to the result of the study conducted by Agyemang and Ofei (2013). The result further explains that OC played a role as a partial mediator between WE a PsychCap.

It is, therefore required for the hospital management to work on such policies through which nurses' PsychCap and commitment level can be increased. Because PsychCap increases employees` OC which leads to WE. While engagement further leads to other positive outcomes, such as high level of performance, job satisfaction, decreased absenteeism as well as turnover (Dajani, 2015).

There are also a few limitations of this study. For example, the data was collected from the three hospitals of KPK through a convenient sample technique. It is suggested that in future the data may be collected from a large population through a random sampling method, in order to further generalize the results. Because of job security in the public sector organizations, the commitment of the employees is normally high as compare to the private sector organizations. It is, therefore in future a comparative study shall be required to investigate the impact of OC as a mediator between PsychCap and WE in public and private sector organizations.