UNDERSTANDING WORK ENGAGEMENT: SIMPLIFIED LITERATURE REVIEW FOR EARLY SCHOLARS

Purpose of Study: The paper aims to guide and inspire early researchers on the topic Work Engagement. The article has worked with particularized review of highly prominent studies on the topic to educate early scholars about the major scholarly developments on the topic. Methodology: Through this, the author has also reviewed and underlined how engagement can be of considerable value towards bringing passion, zeal and zest at work. To article goes further to offer details on the prominent theoretical underpinnings and the notable predictors of work engagement. Towards the end, the article also sheds light on the prominent model of work engagement, popularly known as JD-R model of engagement and the prominent efforts made towards extending in the past to help understand the concept better. Lastly, the paper also sheds light for early researcher on the concept of developmental Resources such as HR infused elements as a major gap that could be added to the JD-R and also considered by other emerging researchers for future research. Results: Overall, this simple yet critical insight-based piece of work provides a healthy piece of understanding and way forward for enthusiasts on the concept of engagement.


INTRODUCTION
Organizations as well as practitioners are fond of conducting research on workplace prospects that could help them make the best out for their business goals. Therein, some of the prominent factors that data suggests is required by organizations is to have engaged employees (Ndungi, 2018). The concept refers to being psychologically connected with the work to bring the best on job (Schaufeli et al., 2002) and studies have worked across different occupational settings to explore and understand the concept. Thankfully, scholars have helped corporate entities and organizational scholars to learn about the different factors that could help predict engagement at work followed by prominent theoretical backgrounds for justification. These findings and results are important to help understand and outline what directions have been taken by researchers over the past decades. Accordingly, critical review of these studies also underlines what gaps are there which could be potentially capitalized by early researchers enthusiastic about engagement to build their scholarly credentials. With this view beforehand, the author of the present article has worked to give a healthy understanding and knowledge to individuals of early researchers to plan paths for scholarly work on the topic. a sense of pride and encouragement (MASLACH and LEITER, 2008). Britt et al. (2001) have also given explanation to the concept which says that engagement brings not only hands to work but also heads with whole hearts. People who are engagement at work they bring the best of their self in terms of physiological and psychological energies. These definitions and explanations by prominent scholars underline a few things. Students who are engaged bring connectivity with the work; they experience p

Definition and Conceptualization of Work Engagement
Engagement has been given many explanations by organizational scholars. With Kahn (1990) being the pioneer in underlining it where he asserted it as a psychological factor what relates to deeper inner self of an individual. The term since then has received much appreciation and attention where it is referred as a positive individual self that boosts individuals to emotionally, physically and mentally give their best in their work (Bailey et al., 2015).
In his following work (Kahn, 1990;Neema, 2018) differentiated engagement from the mental presence of an individual. He has placed arguments suggesting that this is a far higher than just being mentally available whereby, people work with higher commitment, involvement and bonding towards their work responsibilities. Keeping this beforehand, definition of Schaufeli et al. (2002) could be recalled which denotes engagement as a work directed psychological energy that alludes people to work with immersion, vigor and passion.
Another prominent conceptualization to engagement refers to the concept as one that brings a more in-depth of involvement in the work which leads towards personal fulfillment thus bringing leasure in doing a great job and cannot detach themselves from the work which makes them well capable of handling all matters related to work. They express excellent levels of immersion at work and showcase higher dedication commitment and attachment. This is one of the reasons why such people are found to be more capable and willing to go for discretionary efforts (Bakker, 2011). Many features of employees who are engaged have also surfaced through empirical attempts such as socialable, cheerful, resilient, good in coping pressure, stable and inclusive. This also underlines that engagement goes beyond the conventional Prominent authors (Salanova et al., 2005) have outlined that businesses focused on nurturing employee performance require work engaged employees. Similarly, Halbesleben and Wheeler (2008) have also forwarded claims in support of work engagement for responsive employee behaviors and outcomes. Apart from the performance perspective, employee work engagement brings numerous positive attributes to the business. Engaged employees are emotionally, physically and cognitively connected with their work which is why they come to work with high enthusiasm (Buckingham and Coffman, 1999;Okon, 2016). Consequently, Saks (2006) found that work engagement fosters organizational citizenship behavior and reduces intention to quit. Study by Britt et al. (2001) found work engagement facilitating in tackling work stress whereby, Jennifer et al. (2010) found engagement predicting customer loyalty and satisfaction.

Theories Explaining Work Engagement
Numerous theories have been used to explain engagement and its relationships with several job personal, and organizational factors. This includes Conservation of Resources (COR) Theory (Hobfoll, 1989); Social Identity Theory (SIT) (Tajfel et al., 1971); Social Exchange Theory (SET) (Blau, 1964); Role Theory (Kahn, 1990); Broaden and Build Theory (Fredrickson, 2001)  The current study examined JD-R model of work engagement (Demerouti et al., 2001), which asserts a unique interaction and relationship of job demands and job resources in fostering employees` work engagement. To explain this connection and influence, the JD-R model underpins Conservation of resources (COR) theory (Hobfoll, 1989;. The COR theory has been the most widely casted theoretical concept to understand and examine work engagement (Xanthopoulou et al., 2009;Bakker et al., 2011).

Conservation of Resources Theory
The COR (Hobfoll, 1989) asserts that accretion and accumulation of resources is critical for nurturing individual behaviors. The crux of the COR theory outlines that people as individuals are driven towards acquiring, securing and fostering resources and these resources help them to avoid negative consequences. In line to this, the COR theory can be explained with an example that when employees have social support from coworkers, it helps them to showcase positive behaviors at work and avoid any negative consequences like emotions and workload. Moreover, such support would enable them to appreciate these resources and capitalize upon them. Another notion of COR theory is that people must invest in the resources also in order to avoid future complexities. This can be understood with the example of learning new skills to avoid workload and efficiency issues at work.
The COR theory also advocates that value and capitalization of resources may rise particularly when the stressors at work are high (Hobfoll et al., 2003;. For instance, the acquisition, retaining and protection of supervisor support, coworker support will be more positively influencing when job demands like workload and emotional demands will be high. Under the umbrella of this theory, individuals engaged at work would be more capable of negating the effects of stressors (job demands) through mobilizing existing resources and creating new ones. These resources may be based at the job, personal or organizational level; the JD-R model of work engagement (Demerouti et al., 2001;Okpechi et al., 2018) is primarily based on the premise of COR theory which suggests that job resources like (supervisor support, coworker support, meaningful work) enhance employee behaviors at work to predict work engagement. Numerous empirical studies (Hakanen et al., 2008;Xanthopoulou et al., 2009;Caesens et al., 2014) have used COR as the underpinning theory to examine work engagement.
Additionally, the theory also explains the negative influence of work stressors i-e job demands including workload and emotional demands (Hobfoll, 1989). Subsequently, the current study anticipated and examined developmental HR resources including employee training opportunities, career development opportunities and developmental performance appraisal (Kuvaas, 2008) to be significantly enhancing employee behaviors at work thus, predicting work engagement. In line with this explanation, which has also been accepted by past studies (Salanova et al., 2005;Christian et al., 2011), the current study has also empirically outlined developmental HR resources and their association with work engagement under the explanations of COR theory.
Henceforth, whilst following the explanations of COR theory, the JD-R model of work engagement was examined with eight determinants/predictors including supervisor support, coworker support, meaningful work; workload and emotional demands; employee training opportunities, career development opportunities, and developmental performance appraisal, followed by the moderation of service climate in connection to work engagement.
Research on work engagement has showcased job resources as some of the utmost important factors towards explaining work engagement (Bakker and Demerouti, 2008;. In view of these studies, job resources hold massive significance as they help individuals to become psychologically resourceful. Resources have a motivational prospect at work which can enable an individual to pick up momentum to achieve assigned targets (Demerouti et al., 2001). According to Schaufeli and Bakker (2004) job resources have a motivational potential and hence work as antecedents of crucial employee behaviors and outcomes. As Kahn (1992) has asserted that engagement varies based on the perception of people regarding their availability and access as it helps them to connect and energize with the work. Notably, job resources can also potentially help in lessening the deleterious effects of work stressors (job demands), leading towards effective completion and accomplishment of goals and work tasks (Schaufeli and Bakker, 2004).
Therein, studies have outlined acute significance of support features towards nurturing psychological capabilities and facilitating employees to work with more energy and sense of belonging wellbeing thus, inducing work engagement. Empirical research has found that job resources including supervisor support, coworker support, task variety, and performance feedback bring a robust enhancement in employee engagement with their work .
For instance, study on Dutch workers from varied occupational groups (Schaufeli and Bakker, 2004) reported that important resources like supervisory coaching, performance feedback, and social support can significantly foster work engagement. The study found that support from supervisor and help from coworkers along with feedback on their progress was responsively helping employees to remain engaged at work. The study found that these job resources were important for boosting engagement levels of Dutch workers across the various occupational settings. Similar findings were reported in the higher education institutions in South Africa (Breevaart et al., 2014).
In the likely fashion, Bakker and Demerouti (2007) and Hakanen et al. (2006) in their empirical studies on teachers also forwarded significant results with regards to the role of social support, supervisor support, job control on work engagement. Importantly, similar inferences have also been tested in countries like Turkey (Koyuncu et al., 2006). In this study engagement of women working on managerial position in a widely operating commercial Turkish bank were unearthed. The study found that rewards, job control and work life experiences significantly predicted work engagement.
Notably, not just the cross sectional but longitudinal studies have also confirmed the critical worth of job resources towards work engagement. Studies like Hakanen et al. (2008) and Schaufeli et al. (2008) have outlined that job resources like social support boosts positive psychological work state, marking significant cross-lagged impact on future work engagement. Henceforth, job resources can be of great importance for businesses to shape employee behaviors and secure better performance prospects. Importantly, social support features including supervisor support and co-worker support has dominated all other factors in predicting work engagement. This confirms the empirical evidences claiming that when individuals receive adequate support and facilitation from immediate supervisor and co-workers, it improves their work wellbeing and work affiliation.

Individual Personal Factors
Recent studies on the topic of work engagement have outlined individual psychological factors, generally classified as personal resources; holding a significant impact on employees` work engagement. According to Hobfoll et al. (2003), personal resources are healthy, optimistic self-evaluations that refer to one`s mental ability to responsively handle and manage the environmental influences particularly, in critically challenging situations. Study by Xanthopoulou et al. (2007) found that personal resources including self-efficacy, optimism and organization-based self-esteem have a positive relationship. Similar findings were also recorded by Xanthopoulou et al. (2009), demonstrating positive empirical association of personal resources with work engagement. Particularly, the study also outlined reciprocal relationship between personal resource and work engagement.
More recently, Karatepe and Karadas (2015) on psychological capital and work engagement found that the psychological resources including hope, efficacy, optimism and resilience predicted work engagement in the frontline employees of five start hotels in Romania. The study highlights an important dimension of positive psychology underlining that when employees experience higher efficacy, hope and resilience, they set higher targets and work with more enthusiasm and engagement.
In view of this, scholars have also attempted to explore the potential of personality characteristics to be associated with employees` engagement with the work. Kim et al. (2009) and Mostert and Rothmann (2006) in line with this, empirically found that openness, conscientiousness, and extraversion personality types can make a notable impact on employees` work engagement. Although limited, yet still, these findings have strengthened the psychological nature of work engagement and outlined personality influences and their significance in relation to engagement prospects. This also clues towards the fact that ambitious employees, with a firm desire to excel in their job, can potentially demonstrate higher levels of work engagement.
Parallel to this, literature has also indicated towards leader behaviors being significantly related with work engagement (Vogelgesang et al., 2013). These studies have outlined that a leader`s transparency in communication, team support, integrity, effective performance nourishes sub-ordinates` work well-being, leading them to work with greater dedication, energy, and focus (work engagement). In the similar vein, study by Breevaart et al. (2014) outlined the impact of daily leadership styles also. The results found that transformational leadership style had a significantly positive impact on naval cadets` work engagement. Transactional leadership style proved to be less effective compared to transformational yet still; it influenced positively. Consequently, ethics in leadership has also been outlined as crucial for fostering positive work states. Likewise, study by Mulyani (2017) outlined its significant relationship with furthering work engagement. Accordingly, Mujtaba et al. (2018) forwarded positive influence of leader`s relations with the team members with their work engagement. To this point, the literature review suggests that at the organizational level, leadership styles and their behavior traits are important in connection to work engagement. Additionally, since leaders have the authority over all job aspects (Moliner et al., 2008), including the job resources; therefore, how they act and behave results in a major impact on employee work behaviors and outcomes. This also underscores the expression that a leader can act as the foundation towards harnessing and maintaining an environment of work engagement in a business setting. The review suggests that leadership role can be viewed from multiple dimensions in connection to its impact on work engagement. A leader can critically facilitate the engagement process at work through promoting an engaged work environment, communication, leadership style, justice and interpersonal relationships.

JD-R Model of Work Engagement
The current study aimed to investigate JD-R model of work engagement (Demerouti et al., 2001) which is primarily based on the understanding of conservation of resources theory (Hobfoll, 1989). The JD-R model is based on the explanation that every occupation and work setting encompass of some factors that can be categorized into two (i-e job resources and job demands). The JD-R model suggests that job resources like supervisor support and coworker support can enhance individuals` work engagement. The model suggests that social support resources help in boosting psychological work wellbeing (engagement). In addition, it also asserts that job resources are also crucial for negating the bad influences of job demands hence; there is a multi-facet role of job resources in relationship with work engagement.
In parallel, the JD-R model campaigns that job demands such as workload and emotional demands result in burnout, stress and fatigue thus, damaging employees` work engagement. However, job resources may play a further role to negate the deleterious effects of job demands and help keep work engagement intact. The model also argues that the high level of work engagement boosts performance and enables employees to further boost their own resources in future as well (Demerouti et al., 2001). The model suggests that every occupation and work role(s) comes with certain elements that either facilitate employees to bring more psychological resourcefulness at work or takes them to deplete their mental, physical and psychological energies. Thus, the JD-R model refers to an interesting interplay of job resources and job demands towards explaining individual engagement at work. There model forwards consonance to the empirical evidences outlining positive role of job resources towards shaping employee behaviors and outcomes (Hakanen et al., 2006) and job demands in their acting negatively in this regard (Schaufeli and Bakker, 2004;Hakanen et al., 2006).
The current study attempted to enrich knowledge and understanding of work engagement through extending the JD-R model of work engagement (Demerouti et al., 2001). For this, it was essential to review any attempts previously made towards extending the model to build comprehension on the views and assertions of key scholars in the area.
Since its inception in 2001, organizational scientists and academicians started realizing the importance of personal psychological resources and the need to understand the role of work engagement for better employee and organizational outcomes. Work engagement as a concept, has gained significant momentum due to its substantial importance in fostering job performance prospects (Mohammed, 2017).
Nevertheless, despite of this, there have been very limited attempts made in connection to the extension of JD-R model, especially when it comes to the ones endorsed by major authors in the work engagement domain. As understood that work engagement is a psychological state (Schaufeli et al., 2002), (Xanthopoulou et al., 2007) proposed that apart from job demands and job resources, work engagement can also be predicted through personal resources. Personal resources are traits of individual self that are linked to resilience and highlight the potential of individuals towards their ability of handling and managing the impact of environmental components (Hobfoll et al., 2003). The authors proposed and

Attempts towards Extending JD-R model of Work Engagement
However, in a subsequent study by Xanthopoulou et al. (2007) the authors proposed an extension to the JD-R model by stating that components including individual self-efficacy, optimism, and esteem act more likely as a mediator between job resources and work engagement. The authors found more promising mediating effect of personal resources between the job resources and work engagement relationship which conclusively, ended terming personal resources as more potential mediator and not the predictor. This mediation was further confirmed in the follow up study by Xanthopoulou et al. (2009). Albrecht et al. (2015) has outlined that personal resources can significantly enhance mental resilience and competence to tackle environmental challenges and handle pressure at work successfully. The stud also outlined that people with personal resources are more engaged at work and perform better than others. Sadly, this extension has still not be of much of a value due to the fact that personal resources have been questioned as to whether they are antecedents of work engagement or possibly mediators.
In parallel, another attempt towards the extension of JD-R model of work engagement concerned with the element of 'job crafting'. Bakker (2011) suggested that facilitating employees` proactive behavior at work could be another potential arena for consideration in the JD-R model of work engagement. Job crafting is a practice process whereby employees independently shape their work roles (Wrzesniewski and Dutton, 2001). According to Bakker et al. (2011) job crafting is a more special type of proactive work behavior that can significantly enhance work engagement. Bakker et al. (2011) investigated job crafting and forwarded empirical evidence concerning to its relationship with work engagement. The study examined the relationship and found that people, who have the ability and opportunity to craft their job according to their preferences and requirements; exert more energy and engagement at work. has not yet received much importance and empirical importance because of its dubious role. Tims and Bakker (2010) indicated that there are limitations as to what extent an individual with authority to redesign some of their job aspects, would feel better and more motivated towards performing their roles and responsibilities and express work engagement. Accordingly, the authors outlined as to how and to what length the job crafting would yield positive results consistently in the long run is still very unclear. In conclusion, there is a severe lack of empirical confirmation on these attempts towards potential extension of the JD-R model and to what extent that they could be categorized as the direct predictors of work engagement.
In a nutshell, these attempts towards extending the JD-R model have raised many concerns. The first is that, these attempts hint towards the fact that the JD-R model was primarily forwarded by Demerouti et al. (2001) is not responsively robust. Due to which, notable scholars have had attempted to improve it further. These attempts towards extensions also underline the notion that there are major gaps concerning to the JD-R model in order to make it more robust and generalizable in predicting work engagement. The work towards extending the model also highlights that there are several features that could be further explored and effectively incorporated to enhance the contributory value to the JD-R model of work engagement. Schaufeli  In particular, work by Kuvaas (2007) has outlined significance of HR practices that prominently act as developmental resources for employees to boost work aspects. The author has termed them as 'Developmental HR practices' which includes employee training opportunities, career development opportunities and developmental performance appraisal, as the significant factors for boosting employee behaviors and outcomes. Kuvaas has outlined that developmental HR resources can significantly stimulate people and push them to work and give their best. Accordingly, Kuvaas has also indicated towards paucity of research on developmental resources for enriching employee attitudes. Importantly, in connection to work engagement, there is no sound empirical study available, investigating these developmental HR resources, thus highlighting serious theoretical gaps in the engagement literature requiring urgent empirical attention. Based on these suggested shortcomings and potential areas for further enhancement of the JD-R, the current study proposed and examined extension of the model through introducing developmental HR resources.
Henceforth, the paper highlights for early researchers to understand the gaps in research on the developmental resource side. Emerging researchers based on the critical appraisal of the literature have a major gap in this regard to capitalize upon the opportunity and make scholarly contribution.

CONCLUSION:
Conclusively, the paper has worked to underline major developments on the topic of work engagement. The paper guides through providing a detailed view of findings of notable scholars on the topic, the prominent theories underlying the concept and the different factors that can influence it. The paper is a piece of effort for early scholars to understand the concept and underline what has been learned and revealed about it so far in order to plan future investigations accordingly. The paper aimed to inspire early researchers on the topic to engage so they can responsively plan and strategize for addressing the gaps.