Warshawsky, Nora E. PhD, RN; Havens, Donna S. PhD, RN, FAAN; Knafl, George PhD
Improving patient safety in resource-constrained environments is a daunting task facing healthcare organizations. Nonhealthcare, high-performing organizations have demonstrated that the driving force behind top performance is an engaged workforce.1,2 Engaged employees are energized, dedicated, and motivated to persevere and complete their work.3 Managers are critical for creating environments fostering employee engagement.2 Managers must be engaged in their own work to create these stimulating work environments. In healthcare, nurse managers are expected to create motivating work environments for nurses, yet little is known about what motivates nurse managers. This study tested factors that should positively influence nurse manager work performance.
Work engagement is a motivational state characterized by vigor, dedication, and absorption.3 Engaged employees enjoy challenges, exhibit mental resilience, and are engrossed in their work. Whereas many early studies of work engagement were conducted in business settings, studies of work engagement in healthcare are only beginning to appear in the literature. In a literature review, Simpson4 found only 1 study5 of work engagement in nurses. Much of what was studied in nursing related to this concept prior to 2007 was burnout,4 what some consider the antipode of work engagement.6 Subsequent to Simpson’s4 review, 1 study of nurse managers’ work engagement7 and 12 studies of staff nurses’ work engagement8-19 were published. Mackoff7 identified characteristics of engaged nurse managers and work environments that potentially foster engagement in nurse managers. Based on studies of staff nurses, higher levels of work engagement were associated with higher levels of patient satisfaction,12 quality of care,8 and work effectiveness.9 Higher staff nurse work engagement was associated with increased staff nurse willingness to voice concerns about patient care8 and to perform discretionary extra-role behaviors.10 Because staff nurse work engagement was influenced by nurse managers5,8,10 and resulted in proactive work behaviors that promote safe patient care8,10 and improved patient outcomes,8,9,12 exploring nurse manager work engagement might contribute insights as to why some nursing units achieve superior patient outcomes.
The work engagement literature suggests that high-quality interpersonal relationships (IPRs) foster work engagement. Together, work engagement and IPRs may promote proactive work behaviors associated with improved organizational performance. Therefore, the specific aim of this study was to test the influence of IPRs on nurse manager work engagement and proactive work behavior.
Model of Work Engagement
According to the model of work engagement,3,20 job resources and job demands affect the development of work engagement in employees. Job resources are physical, psychological, social, and organizational features that reduce job demands, enhance an employee’s ability to meet work goals, and stimulate personal growth, learning, and development.20 Job resources are obtained from organizational structures, through social and IPRs, from organization of the work, or from the task itself. Job resources found to increase work engagement for managers include autonomy, performance feedback, supportive colleagues, and supervisory coaching.3,20 For managers, job resources could include the quality of their relationships with their peers and nurse administrators.
Job demands are physical, social, or organizational aspects of a job that require sustained physical or psychological effort leading to adverse physical and/or psychological outcomes.20 Job demands may reduce the effects of job resources that foster work engagement, resulting in burnout. Examples include adverse work environments, role overload, role ambiguity, role conflicts, and time pressures. Nurse manager job demands include large spans of control.
Personal resources may also build work engagement.20,21 Personal resources, such as self-efficacy and optimism, are individual traits that can be developed to improve work performance. For a nurse manager, personal resources could include graduate education and nurse manager experience (Figure 1).
Use of a self-administered electronic survey (Qualtrics Labs, Inc, Provo, Utah) facilitated data collection from a large sample of nurse managers working in acute care hospital settings. Participants were recruited using e-mail addresses of nurse manager members of the North Carolina Organization of Nurse Leaders (NCONL) and biweekly electronic communications to members of the American Organization of Nurse Executives (AONE). Procedures were included to promote a high response rate.22,23
Nurse managers were defined as the 1st-line manager of patient care area(s) with 24-hour responsibility for operational, fiscal, and performance accountability. Although “nurse manager” was considered the most common title for participants, there may have been some with a different organizational title but whose duties matched the given definition of nurse manager. Only nurse managers working in acute-care hospitals and in their positions for more than 3 months were included in the study.
A total of 323 participants completed the survey: 139 were members of AONE only (response rate, 13%), 34 were members of NCONL only (response rate, 44%), 4 were members of both AONE and NCONL, and 121 were not members of either organization. Nurse managers from 44 states participated. Of these, 290 participants met the inclusion criteria. An a priori power analysis established that adequate power existed to detect significant relationships if present.
The average nurse manager in this sample was a 47-year-old white woman, had 9.1 years of nursing management experience, and in their current position for 4.8 years. Most held a BSN (51.7%) or an MSN (33.8%). Many respondents also held nonnursing baccalaureate degrees (46.9%) and master’s degrees (43.7%). Supplemental Digital Content 1 (see Table, http://links.lww.com/JONA/A86) presents the sample demographics compared with the 2008 National Sample Survey of Registered Nurses.24 The average span of control was 59.8 (SD, 37.8) full-time equivalents (FTEs) across 1.6 units (SD, 1.0). These nurse managers were responsible for as many as 220 FTEs across 7 patient-care units.
Human Subjects Protection
The institutional review board at The University of North Carolina at Chapel Hill granted expedited approval. Completing the survey implied consent.
Table 1 presents the instruments, subscales, sample items, and reliability statistics.
Interpersonal relationships were measured using the 7-item Relational Coordination Scale (RCS).25 Three items measured the quality of relationships between work groups: shared knowledge, shared goals, and mutual respect. Four items measured the quality of communication based on frequency, timeliness, accuracy, and problem solving versus blaming. The item stems varied and were rated on a 5-point Likert scale.25 Each item was scored 3 times to assess the quality of IPRs among nurse managers, between nurse managers and nurse administrators, and between nurse managers and physicians in relation to improving organizational processes. Only nurse managers were surveyed; therefore, the RCS reflected nurse managers’ perceptions of the quality of IPRs among nurse managers and between nurse managers, nurse administrators, and physicians.
Work engagement was measured using 8 of the 9 items of the Utrecht Work Engagement Scale (UWES).26 Participants rated each item on a 7-point Likert scale (0 = never to 7 = every day) according to how often the participant experienced the feeling described.3 In this study, the item “I am happy when I am working intensely” was inadvertently omitted from the survey. Prior analyses indicated that this item explained the least amount of variance in the absorption subscale,26 which was omitted from several analyses because absorption was not considered a core dimension of engagement.10,11,15,27 Based on further psychometric analyses, Schaufeli and Bakker28 concluded that work engagement was best measured using the full scale. The Cronbach α for the 8 available items was acceptable29 at .89; thus, the total UWES mean score was used for the analyses.
Proactive Work Behavior
Proactive work behavior was measured using the 13-item Proactive Work Behavior Scale (PWB).30 The scale emphasized initiating internal organizational change. The 4 subscales included taking charge, individual innovation, problem prevention, and voice. Respondents rated each item on a 5-point Likert scale (1 = very infrequently to 5 = very frequently) in response to the stem, “How frequently do you….”
Only cases with complete information on the outcome variable (n = 290) were retained for analysis using SAS version 9.2 (Cary, North Carolina). Of the retained cases, there was 1 item missing from the UWES for each participant and few missing values for the remaining variables.
The composite mean RCS score was highest among nurse managers (3.94 of a possible 5 [SD, 0.58]), followed by nurse administrators (3.83 [SD, 0.68]) and lowest with physicians (3.34 [SD, 0.75]). The UWES total mean score was 6.01 (SD, 0.84) of 7. The PWB total mean score was 4.01 (SD, 0.48) of 5.
Potential covariates were selected based on theory and literature. Mean UWES was regressed separately on each possible covariate. Only age (P = .017) was significantly associated with UWES (see Table, Supplemental Digital Content 2, which presents the bivariate regression of PWB and UWES on covariates, http://links.lww.com/JONA/A117). The mean PWB was regressed separately on each possible covariate. Years of nurse manager experience (P < .001), years worked on current unit (P = .050), and age (P = .004) were significantly associated with PWB. Backward elimination, forward selection, and stepwise regression of PWB on years of nurse manager experience, years worked on current unit, and age were used to identify a parsimonious model. Nurse manager experience was the only significant covariate. Based on these findings, age was used as a covariate in regression models for UWES, and nurse manager experience was used in regression models for PWB.
In order for a mediated relationship to be statistically significant,31 3 conditions had to be satisfied. First, RCS scores for each interpersonal group (among nurse managers, between nurse managers and nurse administrators, and between nurse managers and physicians) were significantly related to PWB (P < .001). Second, RCS scores for each interpersonal group were significantly related to UWES (P < .001). Third, the addition of UWES reduced the effect of RCS scores (IPRs) on proactive work behavior. Together, RCS and UWES explained 18.8% to 23.8% of the variance in PWB (Table 2). Utrecht Work Engagement Scale mediated the effects of RCS scores on proactive work behavior and was affirmed with a significant Sobel test as well as nonparametric confidence intervals based on 1000 bootstrapped resamples (see Table, Supplemental Digital Content 3, http://links.lww.com/JONA/A87).
The analyses were repeated, adding age and nurse manager experience to the models. The mediated relationships held and together, RCS and UWES, controlling for age and nurse manager experience, explained 21.6% to 25.4% of the variance in PWB. Given that RCS score for each interpersonal group was significantly associated with UWES and PWB, an additional analysis was conducted that considered the effects of RCS scores of all 3 interpersonal groups simultaneously on UWES and PWB.
Backward elimination, forward selection, and stepwise regression were used to identify which of the 3 interpersonal groups of RCS were significant at the P = .05 level. Only RCS scores with nurse administrators and RCS scores with physicians were included in the additional mediation analysis (Figure 2). First, RCS scores with nurse administrators (β = .103, P = . 017) and RCS scores with physicians (β = .190, P < .001), controlling for nurse manager experience (β = .011, P = .002), were significantly related to PWB. Second, RCS scores with nurse administrators (β = .324, P < .001) and RCS scores with physicians (β = .259, P < .001), controlling for age (β = .013, P = .01), were significantly related to UWES. In the 3rd step, RCS scores with nurse administrators (β = .049, P = .254) became a nonsignificant predictor of PWB. Relational Coordination Scale scores with physicians (β = .149, P < .001) and UWES (β = .164, P < .001), controlling for nurse manager work experience (β = .010, P = .005), however, were significantly associated with PWB and explained 25.7% of the variance in PWB (see Table, Supplemental Digital Content 4, which shows the mediation analysis with full model, http://links.lww.com/JONA/A88).
On average, nurse managers reported they engaged with their work several times a week (mean score, 6.01 [SD, 0.83]), much higher than samples of business managers (4.22 [SD, 1.00])32 and acute care staff nurses working in the United States (4.60 [SD, 0.62]).17 The high level of work engagement suggests that these nurse managers considered the nature of their work to be meaningful, and they possessed sufficient job and personal resources to mitigate the job demands present in their work.20
The mean score for IPRs ranked highest among nurse managers and their peers (3.94 [SD, 0.58]), followed by IPRs with nurse administrators (3.83 [SD, 0.68]) and lowest—and most variable—with physicians (3.34 [SD, 0.75]). Across all groups, nurse managers rated the quality of these IPRs slightly above the midpoint of the scale range, suggesting that all these relationships could be improved. In light of these scores, there may be other job and personal resources not included in the study that contributed to the high work engagement scores of this nurse manager sample. Nurse managers who participated in this study were asked to consider each of these IPRs in relation to quality improvement processes; therefore, the scores may not reflect the quality of these relationships when other work processes are considered.
When IPRs for each group were regressed separately on work engagement, IPRs for each group were significantly associated with work engagement. Relational leadership styles of nurse managers and preceptors have previously been reported to build staff nurse work engagement.8,13,33 These findings are consistent with the model of work engagement,20 suggesting that supervisory and coworker relationships are instrumental in building work engagement.
Multivariate analyses considering the 3 groups of nurse manager IPRs simultaneously revealed that IPRs with nurse administrators were the strongest predictor of work engagement. Interpersonal relationships with physicians explained more of the effect on proactive work behavior than relationships with peers or nurse administrators. Although IPRs with other nurse managers were rated highest, they did not explain any variance in engagement or proactive work behavior beyond that explained by IPRs with nurse administrators and physicians. This suggests that quality relationships with supervisors are an important source of motivation for nurse managers, whereas quality relationships with physicians exert stronger effects on proactive work behavior.
Others8,34,35 studied the effects of IPRs with peers and supervisors on work engagement and reported that coworker relationships exerted more influence on work engagement than supervisory relationships, the opposite of the findings from this study. Wong et al8 concluded that staff nurses’ identification with peer groups was stronger than with nurse managers because of more frequent interaction with peers. The RCS scores, however, accounted for frequency of communication. In fact, of the 3 groups, the nurse managers’ peer relationships were scored the highest in this study, yet they explained the least variance in nurse manager engagement and proactive work behavior. A possible explanation may be the measures used or that the nature of the IPRs of nurse managers may differ from those of business managers and staff nurses.
Proactive Work Behavior
The nurse managers in this study were asked to rate how proactively they responded to medical errors identified in their units. The average PWB score was 4.01 (SD, 0.48) on a 5-point scale, indicating that this sample of nurse managers often responded proactively to medical errors.
Interpersonal relationships should directly and indirectly, through work engagement, influence proactive work behavior.20,21 Bivariate analyses supported positive associations between IPRs for each of the 3 groups and proactive work behavior and also between work engagement and proactive work behavior. Multivariate analyses revealed that work engagement partially mediated the association between each type of IPRs and proactive work behavior. This suggests that the model tested was not inclusive and that other characteristics of the job or social context20,36 may help explain proactive work behavior.
The social context should build psychological safety that enables workers to take risks and persevere in the face of adversity. Collegial relationships between staff nurses and physicians are known to influence the quality of professional nurse work environments and staff nurse job satisfaction.37-39 This study suggests that the quality of IPRs with physicians also influences nurse managers’ proactive work behavior.
Interpersonal relationships with physicians were rated the lowest of the 3 groups studied. Efforts to improve nurse manager perceptions of IPRs with physicians might also influence nurse managers’ willingness to engage in proactive work behavior and improve patient outcomes as well.
Not only did IPRs of nurse managers have varying effects on work engagement, they also exerted varying degrees of influence on proactive work behavior. Although all 3 groups of IPRs were associated with work engagement, IPRs with nurse administrators were the most predictive of nurse managers’ work engagement. Yet it was the nature of the relationship with physicians that most influenced nurse managers’ decisions to proactively act on medical errors and other patient care problems.
Implications for Practice
Because collaborative work environments are more likely to build work engagement and proactive work behaviors in nurse managers, nurse leaders should intentionally create organizational cultures that support collaborative IPRs. Quality IPRs can be developed through organizational design, collaborative recruitment processes, recognition and reward systems, communication strategies, and mentors.25,40,41
Organizational designs, such as reduced spans of control for nurse managers, promote the development of quality IPR with staff nurses by having time to coach and build connections.25 Organizational designs may also improve nurse manager relationships with physicians. For example, employing physicians as hospitalists encourages physicians to align their goals with the organization. By creating partnerships of nurse managers and physicians, responsibility for achieving quality patient outcomes can be shared.
Recruitment processes that include nurse managers, nurse administrators, and physicians help build social networks that increase opportunities to share knowledge and improve communication.41 The inclusion of all team members in the hiring process creates 3 important results. First, teamwork skills of prospective candidates for positions are assessed.40 Second, candidates learn that interdisciplinary teamwork is valued.25 Third, participation in the selection process increases personal investment by the selection team in the success of the newly hired employee.41
Recognition and rewards need to be based on team performance and achievement of shared goals.25 Performance monitoring systems developed to reflect cross-functional performance encourage all disciplines relevant to a process of care to develop quality IPR based on shared goals, shared knowledge, and mutual respect.25 Shared rewards for exemplary team performance reinforce team behaviors.
There were nurse managers who scored at the lower limits of the ranges indicating that they experienced poor IPR, engaged in their work less than weekly, and rarely acted proactively. More research is needed to identify additional factors that contribute to these low scores.
In this study, span of control was treated as a control variable and not a significant predictor of work engagement or proactive work behavior. Future analyses using span of control are recommended.
Limitations included the cross-sectional study design and assumption of temporal sequencing; therefore, causality cannot be confirmed.42 A convenience sample was used and may not be representative of the general nurse manager population; thus, generalizability of findings may be limited. All data were obtained through self-reported surveys. Respondents were assured of confidentiality and asked to respond according to their actual behavior in an attempt to mitigate potential common method bias.43 The participants were primarily female, reflecting the nursing profession. Thus, some of the variance in mean scores may have reflected gender bias rather than variation due to the nurse manager role. The outcome measure of proactive work behavior was used as a proxy for quality and was not a measure of actual patient outcomes. Finally, although the missing item from the UWES-9 may have skewed the analyses, the Cronbach α for the 8 items was .89 and is considered good for an established scale.29
Hospitals are challenged to achieve consistently superior patient outcomes while facing mounting financial constraints. Studies of high-performing organizations suggest that a key to success is an engaged workforce that proactively resolves performance problems. In healthcare, nurse managers are considered an important driver of staff nurses’ work engagement, yet little is known about the determinants of nurse manager performance. The findings from this study fill part of the knowledge gap related to nurse managers’ work engagement and job performance. Although IPRs with peers and physicians influenced nurse managers’ work engagement, it is the nature of their IPRs with nurse administrators that most strongly influenced nurse managers’ work engagement. Furthermore, it was the combination of nurse managers’ work engagement, quality IPRs with physicians, and experience as a nurse manager that most strongly influenced the degree to which nurse managers acted in a proactive manner, an important behavior in the prevention of medical errors and improvement of the quality of patient care. As healthcare organizations respond to the mandates of healthcare reform, nurse managers should be relied upon to actively monitor for and prevent adverse effects on the quality of patient care.
The authors thank Dr Gwen Sherwood, Dr Edward Halloran, and Dr Bonnie Mowinski Jennings for their contributions to Dr Warshawsky’s dissertation.
1. Harter J, Schmidt F, Hayes T. Business unit-level relationship between employee satisfaction, employee engagement, and business outcomes: a meta-analysis. J Appl Psychol. 2002; 87: 268–279.
2. Buckingham M. The One Thing You Need to Know About Great Managing, Great Leading, and Sustained Individual Success. New York: Free Press; 2005.
3. Schaufeli W, Bakker A. Job demands, job resources, and their relationship with burnout and engagement: a multi-sample study. J Organ Behav. 2004; 25: 293–315.
4. Simpson M. Engagement at work: a review of the literature. Int J Nurs Stud. 2009; 46: 1012–1024.
5. Cathcart D, Jeska S, Karnas J, Miller S, Pechacek J, Rheault L. Span of control matters. J Nurs Adm. 2004; 34: 395–399.
6. Maslach C, Leiter M. Early predictors of job burnout and engagement. J Appl Psychol. 2008; 93: 498–512.
7. Mackoff B. Nurse Manager Engagement. Boston, MA: Jones and Bartlett Publishers; 2011.
8. Wong C, Laschinger H, Cummings G. Authentic leadership and nurses’ voice behavior and perceptions of care quality. J Nurs Manag. 2010; 18: 889–900.
9. Laschinger H, Wilk P, Cho J, Greco P. Empowerment, engagement, and perceived effectiveness in nursing work environments: does experience matter? J Nurs Manag. 2009; 17: 636–646.
10. Salanova M, Lorente L, Chambel M, Martinez I. Linking transformational leadership to nurses’ extra-role performance: the mediating role of self-efficacy and work engagement. J Adv Nurs. 2011; 67: 2256–2266.
11. Salanova M, Schaufeli W. A cross-national study of work engagement as a mediator between job resources and proactive behavior. Int J Hum Resour Manage. 2008; 19: 116–131.
12. Bacon C, Mark B. Organizational effects on patient satisfaction in hospital medical-surgical units. J Nurs Adm. 2009; 39: 220–227.
13. Giallonardo L, Wong C, Iwasiw C. Authentic leadership of preceptors: predictor of new graduate nurses’ work engagement and job satisfaction. J Nurs Manag. 2010; 18: 993–1003.
14. Simpson M. Predictors of work engagement among medical-surgical staff nurses. West J Nurs Res. 2009; 31: 44–65.
15. Jenaro C, Flores N, Orgaz M, Cruz M. Vigour and dedication in nursing professionals: towards a better understanding of work engagement. J Adv Nurs. 2010; 67: 865–875.
16. Freeney Y, Tiernan J. Exploration of the facilitators and barriers to work engagement in nursing. Int J Nurs Stud. 2009; 46: 1557–1565.
17. Palmer B, Griffin MQ, Reed P, Fitzpatrick J. Self-transcendence and work engagement in acute-care staff registered nurses. Crit Care Nurs Q. 2010; 33: 138–147.
18. Kuhnel J, Sonnentag S, Westman M. Does work engagement increase after a short respite? The role of job involvement as a double-edged sword. J Occup Organ Psychol. 2009; 82: 575–594.
19. Rivera R, Fitzpatrick J, Boyle SM. Closing the RN engagement gap: which drivers of engagement matter? J Nurs Adm. 2011; 41: 265–272.
20. Bakker A, Demerouti E. Towards a model of work engagement. Career Dev Int. 2008; 13: 209–223.
21. Hakanen J, Roodt G. Using the Job Demands–Resources Model to predict engagement: analysing a conceptual model. In: Bakker A, Leiter M, eds. Work Engagement: A Handbook of Essential Theory and Research. New York: Psychology Press; 2010: 85–101.
22. Dillman D. Mail and Internet Surveys: The Tailored Design Method. 2nd ed. Hoboken, NJ: John Wiley & Sons, Inc; 2007.
23. Hoonakker P, Carayon P. Questionnaire survey nonresponse: a comparison of postal mail and internet surveys. Int J Hum Comput Interact. 2009; 25: 348–373.
25. Gittell J. High Performance Healthcare: Using the Power of Relationships to Achieve Quality, Efficiency, and Resilience. New York: McGraw Hill; 2009.
26. Schaufeli W, Bakker A, Salanova M. The measurement of work engagement with a short questionnaire: a cross-national study. Educ Psychol Meas. 2006; 66: 701–716.
27. Rothman S, Joubert JHM. Job demands, job resources, burnout, and work engagement of managers at a platinum mine in the North West Province. S Afr J Bus Manage. 2007; 38: 49–61.
28. Schaufeli W, Bakker A. Defining and measuring work engagement: bringing clarity to the concept. In: Bakker A, Leiter M, eds. Work Engagement: A Handbook of Essential Theory and Research. New York: Psychology Press; 2010: 10–24.
29. DeVellis R. Scale Development: Theory and Application. 2nd ed. Thousand Oaks, CA: Sage; 2003.
30. Parker S, Collins C. Taking stock: integrating and differentiating multiple proactive behaviors. J Manage. 2010; 36: 633–662.
31. Baron R, Kenny D. The moderator-mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. J Pers Soc Psychol. 1986; 31 (6): 1173–1182.
33. Samuels J, Fetzer S. Evidence-based pain management: analyzing the practice environment and clinical expertise. Clin Nurse Spec. 2009; 23: 245–251.
34. Montgomery AJ, Peeters MCW, Schaufeli W, Den Ouden M. Work-home interference among newspaper managers: its relationship with burnout and engagement. Anxiety Stress Coping. 2003; 16: 195–211.
35. Schaufeli W, Bakker A, van Rhenen W. How changes in job demands and resources predict burnout, work engagement, and sickness absenteeism. J Organ Behav. 2009; 30: 893–917.
36. Grant A, Parker S. Redesigning work design theories: the rise of relational and proactive perspectives. Acad Manage Ann. 2009; 3: 317–375.
37. Kramer M, Schmalenberg C. Staff nurses identify essentials of magnetism. In: McClure M, Hinshaw AS, eds. Magnet Hospitals Revisited: Attraction and Retention of Professional Nurses. Silver Spring, MD: American Nurse Association; 2002.
38. McClure M, Poulin M, Sovie M, Wandelt M. Magnet Hospitals: Attraction and Retention of Professional Nurses. Kansas City, KS: American Nurses Association; 1983.
39. Zanago G, Soeken K. A meta-analysis of studies of nurses’ job satisfaction. Res Nurs Health. 2007; 30: 445–458.
40. Havens D, Vasey J, Gittell J, Lin W-T. Relational coordination among nurses and other providers: impact on the quality of patient care. J Nurs Manag. 2010; 18: 926–937.
41. Baker W, Dutton J. Enabling positive social capital in organizations. In: Dutton J, Ragins BR, eds. Exploring Positive Relationships at Work: Building a Theoretical and Research Foundation. New York: Lawrence Erlbaum Associates; 2007: 325–345.
42. Mathieu J, Taylor S. Clarifying conditions and decision points for mediational type inferences in organizational behavior. J Organ Behav. 2006; 27: 1031–1056.
43. Podsakoff P, MacKenzie S, Podsakoff N. Common method biases in behavioral research: a critical review of the literature and recommended remedies. J Appl Psychol. 2003; 88: 879–903.
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