Discussion
This study aimed to investigate the different psychometric properties of the Justice Perception of Performance Appraisal among the Iranian nurses according to the guidelines proposed by Incarnate Word University. The results of the present study showed that the Justice Perception of Performance Appraisal is a valid and reliable instrument for evaluation of this variable in the socio-cultural context of Iran.
Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to determine the construct validity of the Justice Perception of Performance Appraisal. The main purpose of factor analysis is to summarize a large number of variables into a limited number of factors so that there is the least amount of missed data (18). In this study, the same four factors which were introduced in the main framework were also obtained with acceptable factor loading values. The purpose of exploratory factor analysis is to discover the dimensions of the variable to determine the dimensions of the scale, standardizing the instruments or tests, reducing the dimensions, and evaluating the homogeneity and diversity regarding the construct validity. In this study, the results of exploratory factor analysis indicated the establishment of the four factors of procedural justice, distributive justice, interpersonal justice, and informational justice covering 57.71% of the variance.
Confirmatory factor analysis was also applied to answer the following question: ”can the data in this study confirm the theoretical model which was proposed by the developers of the instrument?”(19). As a result, all the 56 items of the instrument were used as the variables in this study. Given that x2/df = 2.23, the quality of the model was confirmed to allow the assignment of the 56 items to the four theoretically determining factors. Moreover, chi-square, goodness-of-fit index, root mean square residual, root mean square error of approximation, three Bentler-Bont indices, Tucker-Lewis’s index, and comparative fit index were used to evaluate the fitting factor. Accordingly, all these values were indicative of optimal fit. Fit indices of confirmatory factor analysis in the original study which was conducted by the developers of the scale were as follows: RMSEA = 0.13, RMR = 0.049, CFI = 0.95, GFI = 0.86, and Chi-Square(df) = 29.2 (29) (8).
Cranach’s alpha values ​​of 0.7 or above indicate internal stability. In the present study, the Cranach’s alpha coefficient and the intra-class correlation of the instrument were 0.97 and 0.95, respectively, which indicates that the questionnaire understudy has acceptable internal stability for Iranian nurses. Nevertheless, Cranach’s alpha coefficient was reported above 0.87 for all the subscales by the original developers, indicating acceptable reliability of the original questionnaire (8). According to the results of the present study, it can be stated that the Justice Perception of Performance Appraisal is a reliable, repeatable, and adequately stable instrument.
In addition to the desired reliability, the Justice Perception of Performance Appraisal provides multidimensionality which includes four areas of procedural or systemic justice, distributive justice, interpersonal justice, and informational justice. Compared to the organizational justice framework which was developed by Niehoff&Moorman (20), this questionnaire has proposed four main dimensions and more items that indicate higher validity of the instrument.
Although the primary version of this instrument has been used in previous studies (5,21). in Iran, the researchers have only provided some information about the dimensions and the number of items. In other words, they provided insufficient information regarding the analysis of the validity and reliability of Justice Perception of Performance Appraisal (5,21).
Rakhshany Zabol et al. also examined the organizational justice among nurses using Niehoffand Moorman’s proposed scale which helps evaluate organizational justice in 20 items and 3 dimensions (10). The authors had calculated the reliability of this scale in their previous study on a sample of nurses with a Cranach’s alpha coefficient of 0.96. Researchers have only reported the content validity of the instrument based on the opinions of 10 experts but provided no information about the process of assessing the content validity (22). In another study by Mohamed, the relationship between organizational justice and quality of performance among healthcare providers was examined using a researcher-made questionnaire. However, since there is not enough information about the development and psychometric properties of this instrument, it is not possible to have an accurate opinion about its scientific validity and reliability (11).
The majority of the studies related to measuring the nurses’ perception of justice in Iran provide little knowledge about the validity and reliability of research instruments. The validity and internal stability of the Justice Perception of Performance Appraisal showed that the instrument has been translated appropriately and fluently and also the nurses did not face any ambiguity while answering the questions. Besides, the items of the questionnaire were racially and culturally insensitive which can be considered as a distinctive feature for this questionnaire. Although the present study confirms the psychometric properties of the instrument, it is necessary to conduct similar studies using this instrument in the Iranian context to increase the generalizability of the findings. This is the first time that such a scale is validated for nurses’ performance appraisal; hence, it is suggested to investigate the invariance of the factors in this instrument between different groups of respondents in future researches.