Evidence from around the world suggests that the profession of teaching induces a high level of job stress and job burnout. If individuals regularly experience severe job stress and its accompanying physical and psychological effects, they can experience fatigue in both physically and mentally challenging work situations (Brewer & McMahan, 2003; Platsidou & Agaliotis, 2008; Taylor, 1999). The most obvious antecedent of job burnout is job stress, with job burnout regarded as an extension or consequence of a prolonged period of job stress (Hung & Chen, 2009; Schaufeli & Buunk, 2003; Shirom, 2003).

This study focused on the topic of job burnout in relation to teachers, and this study employed the three dimensions of burnout identified by Maslach and Jackson (1981) as the main reference framework; according to the confirmatory factor analysis results of each dimension, the two dimensions of emotional exhaustion and depersonalization were applied as variables. The first goal of this research was to explore the effect of job burnout in teachers, as reflected in their use of instant messaging apps beyond official work hours. 

The rapid development of information technology has gradually changed conventional cognitive approaches toward work, with the boundary between work and personal time being increasingly obscured or disappearing entirely (Derks et al., 2014). Because the work environment of teachers requires them to interact with students, parents, colleagues, and school supervisors, the content of their messages sent using instant messaging apps beyond work hours is both diverse and complex. If instant messaging app use is a long-term work requirement, such use may exert physical and mental pressure for teachers and become a source of stress and a cause of job burnout (Bakker & Sanz-Vergel, 2020; Liu et al., 2019). According to relevant national and international research, teachers’ job stress is divided into three dimensions, namely the 1. stress of teaching, guidance and discipline, 2. administration, and 3. interacting with parents. The second goal of this research was to explore whether teachers use instant messaging apps for work purposes beyond official work hours, and if such use induces job stress, which can lead to job burnout.

An individual’s perception of the value of their work affects their job selection, work behaviors (Lyons et al., 2006), and work attitude (Chu, 2008; Hung & Liu, 2003). To align the dimensions of integrity and separability with general job values, this study used the concepts of self-actualization, organizational safety, and physical and mental health, as proposed by Shen and Huang (2018), as the dimensions of teachers’ job values. Related empirical research has analyzed job values as a moderating variable in the relationship between work stressors and stress consequences, revealing that the job value dimension has a partially moderating effect on work stressors and stress consequences (Siu et al., 2003; Siu et al., 2005). Therefore, the third goal of this research was to clarify the potentially moderating role of job values in the relationship between receiving workrelated messages through instant messaging apps beyond work hours and teachers’ job stress. The study employed questionnaire surveys, with elementary school, senior high school, high school, and vocational high school teachers recruited as study participants. Regarding the target population and the representativeness of the study results, a 95% confidence interval was applied in which the error did not exceed .05. Using stratified random sampling, we administered 911 questionnaires and received 731 completed questionnaires. After the removal of the questionnaires from teachers who did not use instant messaging apps for official business beyond work hours, 717 valid questionnaires remained. IBM SPSS 23.0 and AMOS 24.0 were used for statistical analyses, including data processing, confirmatory factor analysis for each scale, and correlation analysis for each variable. To verify discriminant validity between constructs, we conducted four-factor confirmatory factor analysis. The results of the absolute fit measure index were as follows: χ2 = 2788.748 (reached a significant level), GFI (goodness-of-fit index) = .82, AGFI (adjusted goodness-of-fit index) = .80, RMSEA (root mean square error of approximation) = .057. The results of the relative fit index were as follows: NFI (normed fit index) = .85, NNFI (non-normed fit index) = .88, CFI (comparative fit index) = .89. The parsimonious fit measure index results were as follows: PGFI (Parsimonious goodnessfit index) = .75, PNFI (parsimony-adjusted NFI) = .79, PCFI (parsimonious comparative-fit index) = .83. All of the test results for goodness of fit met the standard of model evaluation; therefore, the structural model used in this research had favorable goodness of fit. Additionally, we applied Hayes’ process model (2013) to detect mediation effects, adjustment effects, moderated mediation effects, and the interactions among various factors. 

The research results indicated that teachers’ use of instant messaging apps for official business beyond work hours and job stress had a significantly positive relationship (r = .429, p < .01); the correlation coefficient of these two dimensions was within .176 and .371, which is consistent with the research results of Lee (2017), Chi and Tsai (2018), and Van Laethem et al. (2018). In addition, we further determined that teachers’ use of instant messaging apps for official business beyond work hours and the overall effects of teachers’ job burnout were significantly correlated (c, r = .221, p < .001), which is in line with the findings of Chi and Tsai (2018), Liu et al. (2019), Sarafino (2001), Taylor (1999), and Van Laethem et al. (2018). 

The results of the overall effect analysis revealed the indirect and significant effect of job burnout (effect = .19, SE = .02, 95% CI = [ .15, .24]), but the direct effect did not reach significance (effect = -.004, SE = .03, 95% CI = [-.07, .06]). This result demonstrated that teachers’ job stress exhibited a complete intermediary effect on the relationship between teachers’ use of instant messaging apps for official business beyond work hours and job burnout. Therefore, teachers’ use of instant messaging apps for official business beyond work hours for a long period shapes their perceived stress, with job stress assuming a mediating role between teachers’ use of instant messaging apps for official business beyond work hours and job burnout. This result aligns with those of Chi and Tsai (2018), Liu et al. (2019), and Binnewies et al. (2009). 

We also employed Model 7 in the SPSS PROCESS macro to test the confidence interval of the indirect effect and conditional indirect effect in the moderated mediation (Hayes, 2013). The indirect effect of teachers’ use of instant messaging apps for official business beyond work hours on teachers’ job burnout reached significance when teachers’ job values were low (boot ab = .211, boot SE = .031, 95% boot CI = [ .153, .275]) and when their job values were high (boot ab = .173, boot SE = .023, 95% boot CI = [ .13, .22]).

However, the average stress of teachers with low-level job values was still higher than that of teachers with high-level job values. Therefore, the long-term use of instant messaging apps for official business beyond work hours caused an accumulation of job pressure regardless of the level of teachers’ job values. This result is consistent with those of Siu et al. (2003) and Siu et al. (2005). 

Finally, we provided some suggestions for schools, educational authorities, principals, and education directors. The results of this study can be used as a reference for other studies on the work-related use of instant messaging apps beyond work hours and teachers’ job stress, job burnout, and job values.