The mediating role of job satisfaction on the relationship between teachers ' perceptions of supervisor support and job performances

The main purpose of this study is to examine the relationship between teachers' perceptions of supervisor support and job performances and the mediating role of job satisfaction in this relationship. The study group consists of 206 teachers working in the public high schools in the Giresun province centre during the 2016-2017 academic year. The study group has been determined by simple randomized sampling method. In the study, the effect of teachers' supervisor support perceptions on job performance and the mediating role of job satisfaction have been tested by forming a structural equation model. According to the results, there is a positive linear relationship between supervisor support, job performance and job satisfaction and job satisfaction has a full mediating role between supervisor support and job performance.


INTRODUCTION
Attitudes and behaviours of the teacher towards the work may affect both the individual and the school-related job outputs.Attitudes and behaviours displayed by the teacher, on the other hand, may be affected by the internal and external stakeholders of the school.In this effect, the support of the school administrators to the teachers has an important part.Supervisor support means the evaluation of the subordinates and their contributions to the organization by the supervisors and supervisors' interest in their contributions (Eisenberger et al., 2002).In other words, it refers to support offered to the subordinates by supervisors in the organizational sense and a positive work relationship between the supervisor and the subordinate (Bhanthumnavin, 2003).Supervisor support is a general idea developed by supervisors by considering the well-being of their subordinates, offering them solid assistance and emotional support (Kossek et al., 2011).In this regard, support of the school administrator means dignification of teachers, evaluation of their work, offering help and development of positive relationships with teachers by school administarators.There is significant relationship between teacher's perception of supervisor support and certain variables.Klusmann et al. (2008) note that support of the school administrator influence teachers' level of taking responsibility.Kahn et al. (2006) also points out that negative relationships between the emotional-social support of school administrators and emotional exhaustion of teachers.Özdemir (2010) also states that supervisor support perceived by teachers at elementary schools is related to organizational citizenship behaviour.
One of the variables with which supervisor support is positively associated is job satisfaction (Babin and Boles, 1996;Baloyil et al., 2014;Demirhan et al., 2014;Griffin et al., 2001;Ng and Sorenson, 2008).Job satisfaction refers to the happiness, pleasure, or satisfaction that employees take from their work.When the literature is examined, it is seen that the concepts of job satisfaction, job pleasure or job contentedness are generally used interchangeably.Job satisfaction (job pleasure) is defined as the pleasurable feeling about the resulting job after the evaluation of one's job " (Robbins and Judge, 2012, p. 77).According to Güney (2011, p. 12), job satisfaction is "the happiness and peacefulness of employees feel when what they gain at the workplace meet their material and spiritual needs".If teacher's job satisfaction means pleasure, enjoyment, satisfaction, happiness and positive feelings the teacher has towards his/her work.In the literature, teachers 'perception of supervisor support seems to be related to teachers' job performance.Tickle et al. (2011) points out that perceptions of teachers' supervisor support greatly influence their job satisfaction and intention to stay in the educational environment and that it mediates student behaviours and educational experiences.Brackett et al. (2010) also states that there is positive relationships between secondary school teacher's perception of supervisor support and their job satisfaction, positive emotions, personal accomplishments and social affiliation and negative relationships between negative feelings and depersonalization (burnout).
One of the variables where supervisor support is positively related to is job performance (Azman et al., 2009;Bhanthumnavin, 2003;Demirhan et al., 2014;Shanock and Eisenberger, 2006;Saleem and Amin, 2013;Pazy and Ganzach, 2009).Job performance means work accomplishment, or the degree of success demonstrated in any job (Demirtaş and Güneş, 2002).The concept of work performance is a concept that expresses to what degree a goal has been achieved at a job and at what level goals have been accomplished.The teacher's job performance is related to how successfully the teacher fulfils his/her duties and responsibilities.A high performing teacher fulfils his/her duties and responsibilities successfully and provides important contributions to the success of the school.Studies have shown that negative physical conditions and intrainstitutional tensions increase the complaints of teachers and cause the performance of the work to decrease; high Uzun and Özdem 85 levels of wages, good communication at school and sincere relationships with managers increase job performance (Akbaba and Kipici, 2015).There is also a significant relationship between teacher perception of supervisor support and job performance.The teacher, supported by the school administrator, experiences the feelings of happiness, peace, determination, effort, confidence, self-importance and trust towards school, power, success and displays higher performance (Argon, 2014).
There is also a positive relationship between job satisfaction, which indicates the general attitude of employees to their work, and job performance (Aydemir and Erdogan, 2013;Demirhan et al., 2014;Harrison et al., 2006;Judge et al., 2001;Schleicher et al., 2004).In addition, it is observed in the literature that there is a significant relationship between job satisfaction and job performance of teachers (Arifin, 2015;Koç et al., 2009).
The following hypotheses have been developed upon reviewing the studies in the literature on supervisor support, job satisfaction and job performance: H1: There is a positive linear relationship between teachers' supervisor support perceptions and job performance.H2: There is a positive linear relationship between teachers' perception of supervisor support and job satisfaction.H3: There is a positive linear relationship between teacher job satisfaction and job performance.H4: Job satisfaction of teachers has a mediating effect on the relationship between supervisor support perceptions and job performance.
The following conceptual model can be developed from hypotheses developed by drawing upon the literature (Figure 1).According to this, there is a positive linear relationship between supervisor support, job satisfaction and job performance.

METHODOLOGY Purpose of the study
The purpose of this study is to reveal the linear relationship between teachers' perceptions of supervisor support and job performances and to test the mediating role of job satisfaction in this relationship.

Study group
The study group of this study consists of 206 primary school teachers that work in 20 different high schools located in the provincial center of Giresun.The study group was determined by simple randomized sampling method.The forms including the scales used were randomly distributed among 250 teachers working at the determined schools; 234 forms were returned, and 9 forms were excluded from analysis due to missing information; while 19 forms were excluded during normality and linearity tests.Thus, a total of 206 forms was used for the analyzes.96 (46.6%) of the teachers involved in the research are female, 110 (53.4%) are male, 33 (16.0%) are between the ages of 22-31; 89 (43.2%) are between the ages of 32-41; 57 (27.7%) are between the ages of 42-51; 26 (12.6%) are between the ages of 52-61 and 1 (0.5%) of them was older than 65.168 (81.6) of the teachers are married and 38 (18.4%) are single.180 (87.4%) of the teachers have a bachelor's degree, 23 (11.2%) have a master's degree and 3 (1.5%)have an associate degree.

Supervisor support scale
The scale developed by Kottke and Sharafinski (1988) has been adapted into Turkish by Özdemir (2010).The 14-item scale is of 5point Likert type (1 = strongly disagree, 5 = strongly agree).As a result of the factor analysis made by Özdemir (2010), it has been understood that 14 items are collected under one factor and the total variance is 0.71.Cronbach's alpha coefficient of the items is 0.96 and the factor loadings are between 0.58 and 0.90.In this study, one dimensional structure was verified by applying confirmatory factor analysis to the scale.The fit indexes of the model according to the DFA result have been calculated as; χ 2 /df=2.14, p<0.001;RMSEA= 0.07, GFI=0.90;AGFI= 0.86, CFI= 0.96, IFI= 0.96, RFI=0.93,NFI=94, RMR= 0.02.In this study, the Cronbach-Alpha internal consistency coefficient of the scale is determined as 0.96.

Job satisfaction scale
The scale developed by Hackman and Oldham (1975) has been adapted into Turkish by Gödelek (1988).The 14-item scale is of 5point likert type (1 = does not satisfy me at all, 5 = satisfies me very much).This scale was applied on teachers by Tasdan ( 2008) and validity and reliability analyses were conducted.According to the results of the study conducted on teachers by Taşdan (2008), the scale is one dimensional.Factor load values of the items included in the scale varies in between 0.69 and 0.86.The total variance expressed by the scale was 64%.Cronbach Alpha internal consistency coefficient of the scale is 0.95.In this study, DFA analysis was done for this research by researcher and one dimensional structure was verified by applying confirmatory factor analysis to the scale.The fit indexes of the model according to the DFA result have been calculated as; χ 2 /df =2.19, p<0.001;RMSEA= 0.07, GFI=0.90;AGFI= 0.85, CFI= 0.90, IFI= 0.91, RMR= 0.06 In this study, the Cronbach-Alpha internal consistency coefficient of the scale is determined as 0.83.

Job performance scale
The scale developed by Kirkman and Rosen (1999) has been adapted into Turkish by Çöl (2008).In the factor analysis by Çöl (2008); it has been found out that the scale has a one-factor structure and the factor loadings vary between 0.781 and 0.807.Cronbach Alpha internal consistency coefficient of the scale is 0.82.In this study, DFA analysis was done for this research by researcher and one-dimensional structure was verified by applying confirmatory factor analysis to the scale.The fit indexes of the model according to the DFA result have been calculated as; χ 2 /df= 4.79, p<0.001;GFI=0.97;AGFI= 0.87, CFI= 0.96, IFI= 0.96, NFI=95.In this study, the Cronbach-Alpha internal consistency coefficient of the scale is determined as 0.80.

Mediation effect
Baron and Kenny (1986) method was followed to analyze the mediation effect.According to Baron and Kenny (1986), some conditions need to be met in order to prove the mediation effect.In the first condition, the independent variable (supervisor support) should have a significant effect on the dependent variable (job performance).In the second condition, the independent variable (supervisor support) should have a significant effect on the mediator variable (job satisfaction).In the third condition, mediating variable (job satisfaction) should have a significant effect on the dependent variable (job performance).In the fourth condition, effects of both independent (supervisor support) and the mediator (job satisfaction) variables on a dependent variable (job performance) are calculated.In such case, the mediation effect may be considered only when the effect of the independent variable on the dependent variable becomes meaningless (Full medium) or decreases (partial medium).

Supervisor Support
Job Performance Job Satisfaction  Tabacknick and Fidell (2001).

Analysis of the data
The statistical analysis of the data obtained in the study was performed on the computer environment with the statistical package programs.Statistical Package for the Social Sciences (SPSS) 21.0 statistical program was used in the evaluation of the data.In the analysis of the obtained data, Structural Equation Model method was used with Analysis of Moment Structures (AMOS) 18.0 program.

FINDINGS
A correlation analysis was conducted to determine the relationships between teachers' supervisor support perceptions, job satisfaction and performance.Relationships between mean and standard deviation values and the variables in the study are shown in Table 1.
When Table 1 is examined, general average of teachers' supervisor support perceptions is calculated as X = 3.68, general average of job satisfaction is calculated as X = 3.24, general average of job performance is calculated as X = 3.96.According to Table 1, there is a significant positive relationship between supervisor support and teachers' job satisfaction (r = 0.45, p <0.01) and job performance (r = 0.26, p <0.01).In addition, there is a significant positive relationship between teachers' job satisfaction and job performance (r = 0.41, p <0.01).
The range of goodness-of-fit values for fitness evaluation of the model are shown in Table 2.

Mediation test with structural equation modelling
Mediating role of job satisfaction in the effect of supervisor support on teacher's job performance has been determined by two different path analyses.Baron and Kenny (1986) method mentioned above has been used as basis to prove the effect of mediation.According to this; in the first model, it has been tested whether supervisor support has a significant effect on job performance.When the first model is examined, it is observed that supervisor support has a significant effect on teachers' job performance (standardized β = 0.28, p <0.05).Thus, the first hypothesis has been accepted.The first model is given in Figure 2.
The goodness-of-fit indexes of the model show that the model is in between acceptable limits (χ 2 /df =1.7, p<0.001;RMSEA= 0.059, GFI=0.90;CFI= 0.97, IFI= 0.97, RMR= 0.052).Standardized beta (β), standard error and significance value of the path from supervisor support to job performance are shown in Table 3.
According to the findings, first condition has been met in the first model.

X
role within the relationship between supervisor support and job performance.Thus, fourth hypothesis has been accepted, too.

DISCUSSION
This study focuses on the relationship between teachers' perceptions of supervisor support, job performance and job satisfaction and to analyze the mediating role of job satisfaction in this relationship.As a result of the study, it has been revealed that there are positive relationships between teachers' supervisor support perceptions, job performance and job satisfaction.
According to the results, there is a positive relationship between teachers' supervisor support perceptions and their job performance and their supervisor support perceptions influence their job performance positively.This result supports the research findings of Akbaba and Kipici (2015), which show that the job performances of the teachers who have intimate relations with their supervisors increase.This is parallel to the research findings of Argon (2014), who has found out that the teacher supported by the school supervisor exhibits a higher performance.In addition, this finding supports the findings of Azman et al. (2009), Bhanthumnavin (2003), Demirhan et al. (2014), Saleem and Amin (2013), Shanock and Eisenberger (2006), and Pazy and Ganzach (2009) revealing that there are positive relationships between supervisor support and employee performance.
According to the results, there is a positive relationship between teachers' supervisor support perceptions and their job satisfaction and their supervisor support perceptions influence their job satisfaction positively.This result overlaps with the findinds of Tickle et al. (2011) pointing out that perceptions of teachers' supervisor support greatly influence their job satisfaction and intention to stay in the educational environment.The findings of Brackett et al. (2010) revealing that there are positive relationships between secondary school teacher's perception of supervisor support and their job satisfaction, positive emotions, personal accomplishments and social appeals also supports this results.This result supports the findings of Babin and Boles (1996), Baloyil et al. (2014), Demirhan et al. (2014), Griffin et al. (2001), and Ng and Sorenson (2008) revealing that there is a positive correlation between job satisfaction and supervisor support.
According to the results, there is a positive relationship between teachers' job satisfaction and their job performance and their job satisfaction influences their job performance positively.This result supports the findings of Arifin (2015), and Koç et al. (2009) revealing that there are significant positive relationships between teachers' job satisfaction and job performances and teachers' Uzun and Özdem 89 job satisfaction influence their job performance.In addition, this result overlaps with the findings of Aydemir and Erdogan (2013), Demirhan et al. (2014), Harrison et al. (2006), Judge et al. (2001), and Schleicher et al. (2004) revealing that there are positive relationships between employees' job satisfaction and job performances.
Another result of this study, job satisfaction plays a full mediating role in the relationship between teachers' supervisor support perceptions and job performances.There are not many studies in the literature focusing on the relationship between supervisor support and job performance (Azman et al., 2009;Bhanthumnavin, 2003;Demirhan et al., 2014;Shanock and Eisenberger, 2006;Pazy and Ganzach, 2009;Saleem and Amin, 2013).Most of these studies focus on the linear relation between the two variables.However, the lack of any studies on the relationship between the two variables is considered as a major deficiency.It is clear that a variable such as job satisfaction, that is closely related to both supervisor support and job performance, may have an effect on the relationship between these two factors.The results of the mediation test conducted to test this idea also show that while teachers' perceptions of supervisor support influence their performances; job satisfaction plays a variable role in this relationship.When job satisfaction is included in the model, supervisor support has no effect on job performance.In a sense, the job satisfactions of teachers participating in the study are shaped by their perceptions of supervisor support in the school; and thus the relationship between supervisor support and teachers' job performances occurs in the context of job satisfaction.This result supports the findings of Judge et al. (2001) examining more than three hundred studies and revealing that there is medium strength correlation between job satisfaction and job performance.
These findings have an important implication for school administrators.Today, improvement of teachers' success, productivity and effectiveness is considered very crucial for all schools.However, if managers do not pay attention to managerial practices, this may negatively affect job satisfaction of the employees, and then may lead to poor performance.Job satisfaction level of the teachers in the study is moderate.Considering that job satisfaction is related to supervisor support, it is necessary for the supervisors to behave thoughtfully and friendly towards the teachers, to show personal interest, to value them, to empathize with them, to listen to and to support their opinions.Teachers having the perception that they are supported by the school managers will have more job satisfaction and this will be reflected in the job performance positively.This will serve to improve of the success and efficiency of schools.This research examines the mediating effect of job satisfaction on the relationship between teachers' perceptions of supervisor support and their job performances.In future studies, researchers may examine the influence of variables such as organizational commitment, justice, and organizational citizenship behaviour as mediating variables on the relationship between supervisor support and job performance.

Table 1 .
Relationships between mean and standard deviation values and variables.

Table 2 .
Goodness of fit values.