The Influence of Role overload and Job control on Job stress

Transcription

1 The Influence of Role overload and Job control on Job stress Name: Jingwen Huang ANR: First supervisor: N.F. Gibson Bachelor thesis Human Resource Studies February June 2017 Tilburg University

2 Abstract Job stress has become one of the commonest problems for organizations because of the high work requirements at the workplaces. Research in the area of job stress has been done many times, however, it still remains unclear to what extent job control can moderate the relationship between role overload and its outcome - job stress. Based on the Job Demands- Resources model, this study hypothesized that role overload is positively related to job stress, and that job control has a moderating effect on the relationship between role overload and job stress. This study applied a Principal Component Analysis (PCA) and multiple regression analysis on a dataset, which is collected by a cross-sectional design. 461 respondents from 82 organizations are approached and filled in the questionnaire. Pearson s r analysis shows that there is a significant relationship between role overload and job stress; job control has no relationship with both variables. Multiple regression analysis shows that role overload has a direct positive significant effect on job stress. However, the results also show that job control has neither significant effect on job stress nor significant moderating effect on the relationship between role overload and job stress. The limitations and practical implications for further research are discussed. Keywords: job stress, role overload, job control, Job Demands-Resources model 2

3 Introduction In a period of the economic crisis, which began in 2008, many organizations had to lay off employees to keep their organizations running. According to the Dutch Central Bureau of Statistics (CBS), employees have been discharged because of the crisis in 2008, which is twice as much as in the preceding year (CBS, 2009). At the same time, however, the amount of work has remained the same, which means that employees have to work more than before to keep the organization running (Toh, Ang, & Devi, 2012). According to FNV, the largest labor union in the Netherlands, more than thirty percent of Dutch employees have problems with work overload and job stress (FNV, n.d.). CBS stated in its report that about 40% of the Dutch employees have to work extra hours to achieve their goals (CBS, 2017). Moreover, about 20% of the employees experience work overload (AOb, 2013). Job stress can be caused by work time pressure, extra work demands and other environmental pressures (Michie, 2002). It can negatively impact the individual employee as well as the organization. On an individual level, job stress might cause dissatisfaction, withdrawal, and eventually turnover (Cherniss, 1980). It can also lead to health problems, such as coronary heart disease and mental problems (e.g. emotional exhaustion, burnout) (Cooperb & Marshall, 2013; Stordeur, D hoore, & Vandenberghe, 2001). For organizations, job stress might lead to poor performance and a low level of productivity (Jensen, Patel, & Messersmith, 2011). Hence, it is of great importance for employees and organizations to reduce job stress. Role overload is one possible cause of job stress (Bolino & Turnley, 2005; Coverman, 1989). Role overload refers to situations in which employees have too many responsibilities or when they are expected to perform well in a limited available time, with only few job resources and under a certain pressure (Bolino & Turnley, 2005; Rizzo, House, & Lirtzman, 1970). Examples are working in a high tempo, and being expected to behave as a good organizational citizen (e.g. having good relationships with co-workers or showing good organizational behavior at work) (Bolino & Turnley, 2005). In line with previous research (Bolino & Turnley, 2005; Maslach, Schaufeli, & Leiter, 2001) and the Job Demands-Resources Model (JD-R model) (Demerouti, Bakker, & Schaufeli, 2001), employees who experience role overload are more likely to experience higher level of job stress. According to the JD-R model, job demands refer to the factors which require physical and/or mental efforts from an individual at his or her workplace (Demerouti et al., 2001). In this case, role overload requires more efforts from an employee, and thus it can be seen as a job demand. When employees experience high role overload, this means that their job demands exceed their capabilities, which will lead to higher levels of job stress (Bolino & Turnley, 2005). 3

4 According to the JD-R model, job demands can be buffered when employees possess plenty of job resources (Bakker & Demerouti, 2007). Job resources are the organizational or social factors, which can help an individual to achieve his or her goals (Bakker et al., 2003). The concept of job control is defined as the perceived ability that an individual can use to influence his or her job to make it more advantageous and less threatening (Ganster, 1989). On the basis of the JD-R model, when employees experience too many job demands (e.g. role overload), and meanwhile there is a lack of job resources (e.g. job control), employees tend to experience more job stress (Jensen et al., 2011). Therefore, if employees want to be able to better cope with job stress, the level of job resources has to exceed the level of job demands. For instance, Boswell and his colleagues (2004) state that employees who experience job stress as a consequence of too many requirements with little job control are more likely to have difficulties to deal with job stress. This study will contribute to the literature because the results will provide more information about the relationship between role overload and job stress by using the JD-R model. Moreover, this study will show to what extent the relationship between role overload and job stress can be influenced by job control. In the past decades, the relationship between role overload and job stress has been examined several times, however, these studies did not examine the moderating effect of job control between role overload and job stress (Coverman, 1989; Jackson, 1989, Bolino & Turnley, 2005; Jensen et al., 2011). Moreover, the results of this study are practically relevant. Examining the relationship between role overload and job stress can help employees and organizations to gain insights into how job stress occurs and how to deal with it. On the individual level, this insight might help employees to better cope with job stress by using their job resources. On the organizational level, managers and HR professionals might come up with better practices to prevent job stress and improve the productivity and work performance. In short, the aim of this study is to test how job control influences the relationship between role overload and job stress. In order to achieve the results, the following research question will be examined: To what extent does role overload influence job stress and to what extent does job control moderate the relationship between role overload and job stress? In the next chapter, the definitions of role overload and job stress will be given and the relationship between them will be explained. Second, the potential moderating effect of job control on the relationship between role overload and job stress will be discussed by using the 4

5 JD-R model. Lastly, the hypothesized relationships and the concept model are presented in Figure 1. Theoretical Framework Role overload First of all, a definition of role overload will be given. Role overload refers to the situation when employees feel that they are having too many responsibilities, or their job demands exceed their abilities to perform well in a certain time with limited resources (Bolino & Turnley, 2005). Employees who tend to fulfill several different roles feel more pressure at their work place, because these roles require additional time, energy, and resources from them (Bolino & Turnley, 2005). Several studies announced that role overload often occurs in association with role conflict, because of the lack of time, energy, and resources, which cannot satisfy the increased job demands (Peterson et al., 1995; Rizzo et al., 1970; Bolino & Turnley, 2005). On the basis of the role theory, employees find it difficult to deal with all their job demands when they fail to execute different roles. As a result, they experience job stress (Bolino & Turnley, 2005). Job stress Parker and DeCotiis (1983) state that job stress is the perception or a feeling of an individual s personal disability that is caused by the events in the work environment. Job stress can be considered as a stimulus, a reaction, but also an interaction between an individual and his or her environment (Parker & DeCotiis, 1983). Furthermore, job stress can be divided into two important dimensions: the time pressure dimension and the feeling of anxiety (Parker & DeCotiis, 1983). Time pressure refers to the feeling of an individual under considerable time pressure, while anxiety refers to the job-related feelings of anxiety. (Parker & DeCotiis, 1983, p. 169). The sources of job stress are called stressors, these stressors can be for example the demands of work itself or situations that interrupt an individual s work-private equilibrium (Lloyd, King, & Chenoweth, 2002). Moreover, continued stress is related to chronic anxiety, psychosomatic illness and a variety of other emotional problems (Lloyd et al., 2002, p. 256). As a result, job stress will impact an individual s health and performance in the long run. Job control Ganster (1989) states in his research that job control is an ability that an individual perceives to utilize his or her work environment in order to reduce threatening and gain more rewards. Job control refers to different aspects of the workplace, for example, work tempo, quality and quantity of production, required techniques, and autonomy (Ganster & Fusilier, 1989). Furthermore, job control is an essential factor of an individual s motivation. In other 5

6 words, an individual has a basic need to control his or her environment (Ganster & Fusilier, 1989). Moreover, job control is associated with an individual s health and performance; employees with a higher level of job control are more satisfied with their job, have better mental health and perform better (Bond & Bunce, 2003). Relationship between role overload and job stress In previous research, job stress has been examined as an outcome of job demands (Bolino & Turnley, 2005; Coverman, 1989; Jensen et al., 2011; Maslach et al., 2001). The Job Demands-Resources (JD-R) model can explain the relationship between job demands (e.g. role overload) and job stress. The JD-R model is a widely recognized model that can be applied to different occupational settings and shows how different job features are associated with employees and organizational outcomes. Moreover, the JD-R model shows how job features can influence one another (Bakker & Demerouti, 2006). Job features are divided into two different dimensions: job demands and job resources. Job demands are physical, psychological, social and/or organizational factors that require physical and emotional efforts from an employee. For instance, high workload pressure, high work tempo, attitude requirements, and uncomfortable work environments are all kinds of job demands (Bakker, Demerouti, & Verbeke, 2004). On the contrary, job resources are physical, psychological, social, and/or organizational factors that a job can offer to the employee to achieve his or her goals, to better cope with job demands, to reduce unnecessary costs, and motivate the employee s self-development (Bakker et al., 2004). Furthermore, job demands elicit a health impairment process, which can explain the relationship between job demands (e.g. role overload) and job stress (Llorens, Bakker, Schaufeli, & Salanova, 2006). According to the JD-R model, the health impairment process begins with chronic job demands, which may deplete employees energy resources and may thus lead to burnout, deterioration of health, and sick leave (Llorens et al., 2006, p ). Accordingly, when employees have to fulfill different roles in the organization, role overload increases, which depletes their energy and leads to job stress. As mentioned earlier, role overload can be classified as a job demand (Bakker & Demerouti, 2007). When an employee experiences role overload, it indicates that the job demands exceed his or her abilities to cope with them, and based on the health impairment process, the level of job stress will increase. Therefore, the following hypothesis has been formulated: Hypothesis 1: The more role overload an employee has, the more job stress he or she will experience. 6

7 Job control as a moderator between role overload and job stress In the previous paragraphs, the JD-R model has been explained (Bakker et al., 2003). As stated, job demands require efforts and energy from the employee, while job resources can help an employee to better cope with job demands to achieve his or her goals (Bakker & Demerouti, 2006). Hence, job demands and job resources are negatively related (Bakker et al., 2003). For example, an employee who experiences a high level of role overload, and as a consequence high levels of job stress, will not be able to cope with the stress when there is an insufficient amount of job resources available. Thus, the balance between job demands and job resources is interrupted. To reduce the level of job stress, an employee needs to gain more job resources. In line with the research by Stiglbauer (2016), job resources buffer the positive effects from job demands on job stress. Furthermore, Jensen et al. (2011) also indicate that employees with more job control experience less job stress. Hence, job control can be seen as a moderator, which can buffer the effect from role overload on job stress. In addition, Bond and Bunce (2003) state that when an employee has more job control, his or her work performance will be improved as well as his or her level of job satisfaction and mental health. They state in their research that ( ) there appears to be consistent evidence that high levels of worker control are associated with low levels of stress-related outcomes, including anxiety, psychological distress, burnout ( ) (Bond & Bunce, 2003, p.1058). In addition, the above-mentioned effect from job control on job stress has been examined several times (Ganster, 1989; Ganster & Fusilier, 1989; Bond & Bunce, 2003; Jensen et al., 2011). Most of these studies state that job control is negatively related to job stress. Jensen et al. (2011) claim on the basis of the job demands-control theory (Karasek, 1979), that job stress is a function of job demands and job control. For example, two employees may respond differently when they are facing the same number of job demands, because of the differences between their degrees of job control and how they fulfill their roles (Karasek, 1979; Jensen et al., 2011). Moreover, Boswell, Olson-Buchanan, and LePine (2002) state that job control has a moderating effect on job stress, if an employee is facing high job demands, and has a low job control, this employee will experience higher levels of job stress as compared to an employee with a high job control. Hence, job control can be expected to serve as a moderator in the relationship between role overload and job stress. This leads to the second hypothesis: Hypothesis 2: The relationship between role overload and job stress is moderated by job control so that the positive relation between role overload and job stress will be reduced under the condition of high as compared to low job control. 7

8 Figure 1: The conceptual model Method Procedure This study has been conducted by HR students of Tilburg University in The design was cross-sectional and quantitative. All respondents were selected by convenience and implicit stratified random sampling. The organizations and departments included both companies within and outside the Netherlands and from different sectors. First, the students used convenience sampling design to gather the data, they were free in their choice of organizations and departments. As a requirement, every participating department should consist of at least seven employees. Altogether, 82 organizations and 101 departments were approached by the students. Second, the sample frame was set up on the basis of job tenure and birth date. By using implicit stratified random sampling, five employees of each department were chosen as respondents of the sample. The aim of this design was to collect a representative dataset of different kinds of employees. A cover letter was sent together with the questionnaire to explain the aim of this study, the importance and the content of the questionnaire. The respondents signed a verification form to ensure that the information they filled in was reliable. 505 employees were invited to participate in this study, 461 employees filled in the questionnaire and returned it to the students, and thereby the response rate was 91.3%. Population and sample The sample consisted of 461 employees from different organizations and departments. After having deleted the missing values by using list-wise deletion, 41 cases were left out and thus the final sample included 420 respondents. Table 1 shows the demographic characteristics of the sample. 39% of the respondents were male and 61% were female. The average age of the respondents was 38 years old. Furthermore, 50.6% of the respondents had higher or academic education, 33.9% had middle education, 14.5% had basic education, and 1.1% had elementary 8

9 education. Moreover, 15.4% of the respondents worked less than 12 hours per week, 83.2% worked between 12 hours and 40 hours per week, and 1.4% worked 40 hours or more per week. Table 1 Demographic characteristics of the sample Characteristic N Frequencies Percentage Gender 451 Male Female % 61% Age 445 Mean 38 SD 13 Education 449 Elementary Basic Middle Higher Academic % 14.5% 33.9% 31% 19.6% Work hours per week 436 < > % 83.2% 1.4% Measures All respondents rated themselves in a self-reported questionnaire in terms of role overload, job control and job stress. All scales of the factors were tested on validity and reliability before the analyses were conducted. In order to verify the validity of the construct, a Principal Component Analysis (PCA) with Varimax rotation was conducted. Regarding the criteria of factor analysis, the Kaiser-Meyer-Olkin (KMO) measure must exceed.6 and Bartlett s test of sphericity must be significant. Moreover, Eigenvalues (equal or higher than 1) were used to determine the number of scales. After that, Cronbach s was considered together with Cronbach s if item deleted to conduct the reliability analysis. Cronbach s higher than.7 was considered as an acceptable value (Tavakol & Dennick, 2011). Cronbach s if item deleted was considered to 9

10 make sure that each item contributes positively to the scale, when the item is deleted, this Cronbach s should be lower than the original Cronbach s. Job Stress. Job stress represents the feeling of an individual who is required to divert from a normal functioning in his/her job as the results of opportunities or demands to the jobrelated outcomes (Parker & DeCotiis, 1983). The items which measure the job stress are from the study of Parker and DeCotiis (1983), an example question was: Working here leaves little time for other activities (Parker & DeCotiis, 1983, p.169). The answers were scored on a 5- point Likert scale (1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree, 5 = strongly agree). KMO was.860 (>.6) and Bartlett s test of sphericity was significant (Chi-Square = , df = 15). Factor analysis showed one factor on the scree plot. Moreover, there was one Eigenvalue higher than 1 (Eigenvalue = 3.477) which suggested that there is one factor in the scale. This factor explained 57.95% of variance. Construct validity was sufficient. The reliability of the scale was good ( =.845), one of the item s Cronbach s if item deleted value (.859) did exceed the original scale s Cronbach s ( I feel guilty when I take time off from job. ). The difference between the values of these Cronbach s was too small (.014), and it was considered as negligible. This item was thus not deleted from the scale. Job control. The items of this variable are taken from the study by Spreitzer (1995). An example question was: I have a great deal of control over what happens in my department (Spreitzer, 1995, p.1465). These items were scored on a 5-point Likert scale (1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree, 5 = strongly agree). The KMO was.758 (>.6) and the Bartlett s test of sphericity is significant (Chi-Square = , df = 15). Furthermore, factor analysis showed two factors according to the scree plot and the Eigenvalues (Eigenvalue = and 1.403), they explain total 74.57% of the variance. Thus, construct validity was sufficient. Even though there are two factors in one scale, both of them measure a similar dimension, thus the first factor ( Autonomy in job, Eigenvalue = 3.071) is considered in the following analysis (Smith, Tisak, Hahn, & Schmieder, 1997). Scale reliability was also good, Cronbach s =.809. No Cronbach s if item deleted values exceed the scale s Cronbach s. Role overload. The items of this variable are taken from the study by Cousins, Mackay, Clarke, Kelly, Kelly, & McCaig (2004). An example question was: I am pressured to work long hours (Cousins et al., 2004, p.130). These items were measured on a 5-point Likert scale (1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree, 5 = strongly agree). The KMO measure was.892 (>.6) and Bartlett s test of sphericity was also significant (Chi-Square = , df = 28). Moreover, factor analysis (PCA) in association with Varimax rotation 10

11 showed one factor in this scale, Eigenvalue = This factor explained 54.79% of the variance. Hence, construct validity was sufficient. The reliability was good, Cronbach s =.880. None of the Cronbach s if item deleted values exceed the original Cronbach s. Control variables. Three control variables were included as dummy variables in the analysis to control for spuriousness. These variables are measured on a nominal scale (such as gender and age). First, according to previous research, gender influences job-related outcomes, such as job stress and burnout, where female employees are more likely to experience negative outcomes than male employees (Purvanova & Muros, 2010). Furthermore, Karasek (1990) indicated in his research that male employees with high level of job control have lower levels of sickness than female employees. The answer categories of gender were Male = 0 and Female = 1. Second, the variable working hours per week of the respondents was included because there is evidence that job control and time pressure are strongly related (Stiglbauer, 2016). Lastly, age has also been included as a control variable. According to Mauno, Ruokolainen, and Kinnunen (2013), age has an influence on coping with job stress and workload. They stated that younger employees are less good than older employees in coping with job stress. The answer category for age was expressed in year and month of birth, and it was converted into age by calculating 2015 minus the year of birth. Analysis First of all, the Pearson correlation (Pearson s r) analysis was examined. The aim of this analysis is to check out whether the variables: role overload, job control, job stress and control variables are in association with each other. Secondly, the Multiple Linear Regression analysis was executed to convey the relationship between the variable of interest and its related predictor variables (Montgomery, Peck, & Vining, 2012). In the first model of the Multiple Linear Regression analysis, only the control variables were added. The aim was to verify whether these control variables had an effect on job stress. In the second and third model, the independent variables, role overload and job control, were added to examine whether they had a direct effect on job stress; while in the fourth model, the interaction effect of job control was tested. Moreover, all analyses were conducted with a significance level of.95 or higher. Besides, the Variance Inflation Factor (VIF) indicated if there were high correlations between predictor variables, which might have led to unreliable regression coefficients. Results Pearson s correlation and descriptive analysis 11

12 Table 2 shows the means, standard deviations, and the correlations between each variable. First of all, a significant effect was found between role overload and job stress (H1) (Pearson s r =.511, p <.01). Secondly, no significant effect was found between role overload and job control, as well as the relationship between job stress and job control. Thirdly, the control variables are also included in Table 2, a significant effect was found between role overload and working hours (Pearson s r =.143, p <.01); a significant negative effect was found between gender and job stress (Pearson s r = -.102, p <.05); also, a significant positive effect was found between job control and all three control variables. The Pearson s correlations between control variables are not relevant for testing the Pearson s correlations between the main variables: role overload, job control and job stress. Table 2 Shortened correlation matrix (N=420) with mean, standard deviations and bivariate correlations (Pearson s r). M SD Role Overload Job Stress ** 3.Job Control Gender * -.151** 5. Age * Working hours ** ** ** Note: ** = correlation is significant at the 0.01 level (2-tailed); * = correlation is significant at the 0.05 level (2-tailed); M = sample mean; SD = standard Deviation; Gender was coded 0 (male) and 1 (female). Role overload and job stress. Hypothesis 1 stated the more role overload employees experience, the more job stress they will experience. Based on the results of regression analysis (table 3, model 2), there is a significant positive effect from role overload on job stress (β =.507, p <.01). The model explains around 32.4% of the variance in job stress (R 2 =.324, p <.01). Furthermore, the value of Fchange (37.057, p <.01) is significant, that means there is a significant improvement when the variable role overload has been added. Hence, the more role overload employees experience, the higher the level of job stress they experience. Therefore, the first hypothesis has been confirmed. Role overload and job stress with job control as a moderator. Hypothesis 2 stated that job control has an influence on the relationship between role overload and job stress. First, 12

13 the results of Pearson s correlation analysis showed that there is no significant relationship between job stress, job control and job stress. Hence, job control was unrelated to role overload and job stress. Second, the results of the regression analysis showed that there is no significant direct effect of job control on job stress (β = -.031, p >.05, table 3, model 3), when job control is entered, it explains around 32.5% of the variance in job stress (R 2 =.325, p >.05). The results indicated that the model is not significant improved, because the value of Fchange is not significant (Fchange = 9.384, p >.05, table 3, model 3). Furthermore, the moderating effect of job control on role overload and job stress has been added in model 4. The results of model 4 did not show a significant moderating effect (β =.042, p >.05, table 3, model 4), this model explains 32.7% of the total variance (R 2 =.327, p >.05). The value of Fchange is not significant (Fchange = 6.134, p >.05, table 3, model 4), which means there is no improvement in the model s fit when job control is added as moderator. Hence, job control has no buffering effect on the relationship between role overload and job stress, and the second hypothesis is not supported. Table 3 Multiple Linear Regression analysis: Role overload, Job stress, with moderator job control. Model 1 (β) Model 2 (β) Model 3 (β) Model 4 (β) Role overload.507**.506**.502** Job control Role overload x Job control.042 Gender Age * -.104* -.101* Working hours.264**.207**.210**.210** R R 2 change.072**.252** F F change ** ** Note: ** = correlation is significant at the 0.01 level (2-tailed); * = correlation is significant at the 0.05 level (2-tailed) Discussion The purpose of this study was to examine the relationship between role overload and job stress, and the moderating effect of job control on this relationship. This study had a specific 13

14 focus on the moderating role of job control because it is still unclear to what extent job control can influence the relationship between role overload and job stress. The central theory of this study is the job demands-resources model (JD-R), which is designed, by Demerouti, Bakker and Schaufeli (2001) and nowadays it is widely used to explain the relationships between different components in an organization. A cross-sectional design was used to collect data, finally, 461 respondents were approached from 82 organizations. The results of this study showed that there is a positive effect from role overload on job stress (H1). However, the results also showed there is no significant moderating effect of job control. In short, a higher level of role overload leads to a higher level of job stress, job control has no influence on job stress when role overload is appearing (H2). According to the results of the analysis for Hypothesis 1, the higher the level of role overload an employee experiences, the higher the level of job stress this employee experiences. This result is in line with earlier mentioned studies, which found that job stress will increase when role overload increases (Llorens et al., 2006; Bolino & Turnley, 2005). This finding is also in line with the JD-R model, which suggests that when job demands (e.g. role overload) exceed the ability of an employee, this will likely increase the levels of job stress (Demerouti et al., 2001). Hence, the first hypothesis on the relationship between role overload and job stress has been confirmed. Secondly, the results of this study did not support the second hypothesis about the moderating effect of job control. Theoretically, the more job control an employee has, the better work he or she can do, which means it will lead to a lower level of job stress (Bakker & Demerouti, 2006; Jensen et al., 2011; Karasek, 1979). In addition, according to the JD-R model, when job resources (e.g. job control) exceed job demands (e.g. role overload), there will be less effect on adverse outcomes such as job stress (Demerouti et al., 2001). However, the results did not show a significant buffering effect of job control. There are some reasons that might explain why this assumption is not supported. First, the direct effect of job demands and job control on job stress are more easily detected than interactive effects (Häusser, Mojzisch, Niesel, & Schulz-Hardt, 2010). Second, the moderating effect of job control occurs when there is a better demand-control match (Stiglbauer, 2016). For instance, cognitive demands (e.g. time pressure, workload) are associated with cognitive control (e.g. timing autonomy). However, the results of these so called matches are afterwards provided after the analysis has been executed, which means these matches are not affirmatory (Stiglbauer, 2016). In other words, the results of the analysis decide if it is or not a good match between two concepts, this makes a good match unpredictable. The question whether job demands (e.g. role overload) with a match (e.g. timing 14

15 autonomy) will actually influence job stress remains to be examined. Moreover, the concepts such as role overload and job stress have diverse components (e.g. emotional, cognitive). When the effects of job demands and resources with these components on the job stress are placed on the different dimensions, the effects will be weaker than they are on the same dimension (Stiglbauer, 2016). For example, cognitive resources (such as job control) should have moderating effects of cognitive demands (such as time pressure) on cognitive outcomes (such as job stress). In this study, the job demands (e.g. role overload) is not in line with the cognitive resources (e.g. job control), hence, the moderating effect of job control is weaker on job stress. Limitations and future research This study aimed at explaining the relationship between role overload and job stress and finding out whether job control plays a moderating role in this relationship. However, there are still several limitations, which need to be taken into consideration. This section contains these limitations and several suggestions for future research. First of all, the cross-sectional design was applied in this study. The disadvantage of this design is that the causation among the variables cannot be shown, which means it is difficult to observe whether job stress is caused by role overload or the other way around. Furthermore, the data was collected at one point in time, which means that the quality of this data was dependent on the status of the respondents at that point in time (Straits & Singleton, 2011). Therefore, the effects of job control on job stress could not be observed in the long run. Hence, it is recommended for future research to use another design such as a longitudinal design. This design measures the same variables at several points in time, meaning that the causal direction, or the patterns of change can be observed (Straits & Singleton, 2011). The second limitation of this study is that the data was collected by using a self-reported questionnaire, which means the respondents themselves estimated the scores. This self-reported method might lead to some common method variance issues, job control and job stress were measured by similar response formats, the reliability and validity of this given information from the respondents are thus unclear and uncertain (Jackson, 1989). For instance, the respondents might tend to answer the questions in a socially desirable way, the quality of the data will be thus interfered and could not reflect the real status. The recommendation for future research is to make use of (semi-structured) interviews instead of questionnaires. This method (e.g. short interview) might obtain more information about the measured variables in the past certain period to avoid earlier mentioned common method variance issues. Moreover, the questionnaire of this study contains more than 100 questions, which is a considerable number of questions that require a lot of time and high concentration of the 15

16 respondents. The latter has some negative consequences. Firstly, the questions are not fully answered, which means the data is not complete and the scale of the useful data is smaller than expected. Secondly, the questions might have been answered less accurately, as when respondents lose their concentration, they tend to read the questions very quickly and give an answer without thinking, hence, the quality of the data might be lower than it is expected. Thirdly, respondents are not able to give the suitable answers because some of these questions were not applicable to them, which means the scores did not reflect the reality. Future research could use a shorter and more specific questionnaire and add an answer category of Not applicable. The fourth limitation concerns the research sample. This study used convenience sampling, which is a non-probability sampling method choosing respondents based on their accessibility. The advantages of this sampling method are that it costs very little time and money (Marshall, 1996). However, the disadvantages of this method could also not be neglected. The well-known issues of convenience sampling are the poor quality data and the lack of intellectual reliability (Marshall, 1996). Future research could make use of simple random sampling, where the respondents are chosen randomly from a population, so the sampling will be more representative of the population. Practical implications As job stress has a negative impact on many different aspects such as employees health status, performance, satisfaction, and turnover, organizations should pay more attention on how to deal with it (Cherniss, 1980; Cooperb & Marshall, 2013; Stordeur et al., 2001; Jensen et al., 2011). As aforementioned, role overload is positively related to job stress, which means that the practitioners should pay more attention to prevent role overload and implement effective HR practices to reduce role overload. On the individual level, employees should be aware that when they are overloaded by their roles. According to the HR experts (Appendix B) and several studies, these roles can be work-related roles (e.g. employee, colleague, or team member) or family-related roles (e.g. parent, brother or son) (Bolino & Turnley, 2005; Greenhaus & Beutell, 1985). It is important for practitioners to be able to separate work-related roles and familyrelated roles, because when an employee cannot handle these different roles, conflict between these roles easily arise and will lead to even more negative consequences (e.g. poor performance) (Greenhaus & Beutell, 1985). On the organizational level, an organization should be prepared to give more support and training to the employees. For example, HR practitioners (Appendix A) suggest that they should develop more effective practices and update already existing practices to help employees deal with their work-related stress. 16

17 There are still useful implications for practitioners, even though no significant buffering effect has been found between job control and job stress. First, the concept of job control can be more specifically defined for employees and employers, which means that the practitioners know exactly what job control entails. Second, practitioners should be aware that job control is a means of reducing employees job stress. According to a meta-analysis by Spector (1986) and the HR experts (Appendix A), practitioners should give more autonomy and participative decision-making to their employees, because the high levels of autonomy and job control the employees perceive, the less job stress and health problem they have, which means the employees are more motivated and satisfied with their job (Spector, 1986). Moreover, the practitioners should also take a look into other potential resources (such as participative management, resilience) which can help employees to better cope with job stress. (Jackson, 1989). Conclusion The aim of this study was to give insights into the relationship between role overload and job stress, and the moderating role of job control on this relationship. This study found that there is a direct positive effect of role overload on job stress. However, this study also has an unexpected outcome, namely, there is no moderating effect of job control on the relationship between role overload and job stress. These findings might give an inspiration to future research, to examine to what extent job control influences job stress, which kind of role does job control play in the relationship between role overload and job stress, and what are the other possible job resources which might have moderating effects on the relationship between role overload and job stress. 17

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22 Appendix A Interviews Interviewer: Jingwen Huang Respondent: Elly van Vliet Function respondent: External Talent Scout Organization: Adecco Group Nederland Datum: 24 April, 2017 Location: Zaltbommel Duration: 45 min Interviewer: Jingwen Huang Respondent: Anouk Rasenberg Function respondent: HR director Organization: Adecco Group Nederland Datum: 18 May, 2017 Location: Zaltbommel Duration: 20 min To gain more insights into how do role overload, job stress and job control influence each other in the reality, a HR expert and a HR director from one of the biggest HR organization were interviewed. Because of the different tasks and roles for these two HR professionals, this report is divided into two parts to analyze above-mentioned variables. The first part is from the individual perspective and the second part is from the organizational perspective. The HR specialist has more than 30 years work experiences in the human resource work field. She works often in a team with co-workers from the different settings in the organization. First of all, the HR specialist indicated that role overload does have influence on job stress, especially when the employees get too many roles and cannot fulfill them all at once. The HR specialist stated that there are two kinds of roles, the formal roles (e.g. employee, team member) and informal roles (e.g. family member, friend). When employees cannot combine these roles, the conflict between work and family will exist, which might influence the performance of the employees. Furthermore, according to the HR specialist, job control does not play an important role in the relationship between role overload and job stress. Though, the employees have to follow some work patterns, but still, most of them has sufficient autonomy to decide how they do their work to achieve their goals. The HR specialist sees the ability to refuse an unwanted role also a kind of job control. It is important for employees to know where the limit is for them to be able to fulfill their tasks. Moreover, the HR specialist indicated that job stress does not always have negative influence. According to her work experience, adequate job stress might stimulate employees to work more efficient and better. In the reality, motivations and organizational support are very important to employees, only when they are motivated, they are willing to put more effort on their tasks. 22