We included nurses from five municipal hospitals in Zhengzhou, Henan province, China. The trained interviewers were from the Medical Affairs Department of the participating hospitals. Of the 900 distributed questionnaires, 792 (88.0%) were recollected and considered valid. Among the 792 participating nurses, 40 were male and 752 were female. The mean age of the participants was 28.8 years (standard deviation, 5.4 years), and the mean duration of working experience was 7.5 years (standard deviation, 5.9 years). The inclusion criteria for taking the questionnaire survey were: aged ≥18 years, more than one year working experience at current position, and no physical or mental illness.
Maslach Burnout Inventory–General Survey
Burnout syndrome was assessed using the Maslach Burnout Inventory–General Survey (MBI-GS) , which was previously translated into Chinese with good reliability and validity in a Chinese sample [9, 10]. The MBI-GS consists of 3 dimensions with a total of 15 items rated on a Likert scale from 0 to 6 points: exhaustion (EX, 5 items), cynicism (CY, 4 items), and professional efficacy (PE, 6 items). The score for each dimension is the sum of the items within that dimension. The level of burnout is positively related to the score. Because PE is scored in an opposite direction, the PE level is negatively associated with the PE score. Cronbach’s alpha of the scale in this study was 0.825.
Measurement of depression
Depression was assessed using the Center for Epidemiological Studies Depression Scale (CES-D) to determine the frequency of depressive symptoms during the past week . The CES-D consists of 20 items rated on a Likert scale from 0 to 3 points. The score is divided by the sum of all items, while items 4, 8, 12, and 16 are scored in the opposite direction. Higher scores on the CES-D indicate higher levels of depression. The total score ranges from 0 to 60 points; ≤16 points indicates the absence of depressive symptoms, 17 to 20 points indicates symptoms suspicious for depression, 21 to 24 points indicates clear depressive symptoms, and ≥25 points indicates severe depressive symptoms. Cronbach’s alpha of the scale in this study was 0.95.
Measurement of job performance
The job performance scale used in this study was a modified version of the Motowidlo scale by Taiwan scholar Yu Decheng, which has been shown to have good reliability and validity . It is divided into task performance and peripheral performance. Job performance consists of 11 items rated on a Likert scale from 1 to 5 points, where higher scores indicate higher levels of job performance. Task performance is assessed by items 1 to 6, which measure work efficiency, quality of work, and other factors related to the work itself. Peripheral performance is assessed by items 7 to 11, which measure whether staff members make extra efforts to help colleagues initiating problem solving, how they deal with interpersonal relationships, and other aspects of peripheral performance. Cronbach’s alpha of the scale in this study was 0.902.
Measurement of personality type
Personality was assessed using two scales of the simplified Chinese version of Eysenck’s Personality Questionnaire-Revised (EPQ-RSC) . It includes 24 items, each scoring either 0 or 1. The neuroticism scale (EPQ-N) assesses emotional stability while the extroversion scale (EPQ-E) assesses the need for emotional stimulation. Each scale is divided into high and low categories based on the medians as the cut-off points reported in literature; this is an accepted method for analyzing psychometric scales . A high score is defined as an EPQ-E C60 and an EPQ-N C61. Four personality types were classified: introvert stable (low EPQ-E, low EPQ-N), extrovert stable (low EPQ-E, high EPQ-N), extrovert unstable (high EPQ-E, high EPQ-N), and introvert unstable (high EPQ-E, low EPQ-N).
Data were input using EpiData 3.1, and statistical analyses were performed with SPSS (version 18 for Windows; Chicago, IL, USA) and Amos 18.0. A two-tailed test at P<0.05 was considered statistically significant. A partial correlation analysis was used to analyze the associations of burnout and depression with job performance and personality type, controlling for sex. Numerical variables are presented as mean ± standard deviation. t-test was used to determine the differences between two groups, while analysis of variance was used to compare multiple groups. If the results of the analysis of variance were significant, post hoc Bonferroni tests were performed to verify the differences between the specific groups.
According to the SEM established by Zhonglin et al. , nurses’ job burnout, depression, and job performance interact with one another and impact job performance. Age, length of service, title, education, department, personality type, and other individual characteristics along with the burnout, depression, and performance scores were entered into the equation to fit the test, and the unmarked path was deleted. An SEM generally evaluates the fitted model to determine the degree of fit between the theoretical model and the actual sample data model. The most commonly used evaluation indicator for the data-fitting effect of the evaluation model is χ2. If there is no statistical significance, then the model is better fit. If χ2/df is <3, the model can be considered better fit . In addition, according to the χ2 and the seven evaluation indexes for the combined assessment method proposed by Zhonglin et al. , we used χ2/df, goodness of fit index (GFI), adjusted GFI (AGFI), normed fit index (NFI), comparative fit index (CFI), incremental fit index (IFI), and root mean square error of approximation (RMSEA) as the evaluation criteria for model fitting. Higher values for these indices indicate a more accurate model. The GFI, AGFI, NFI, CFI, and IFI range from 0 to 1. When χ2/df<3 and the GFI, AGFI, NFI, CFI, and IFI are >0.9, the model is better fit. A smaller RMSEA value is better; a value of >0.1 indicates a poor degree of fit, 0.1 to 0.08 indicates a moderate degree of fit, 0.08 to 0.05 indicates an acceptable degree of fit, and <0.05 indicates the best degree of fit.