Abstract:

In 2013 the amount of migrant workers in China reached 268 million, with an increase of 6.33 million compared to that in 2012 (China National Bureau of Statistics, 2014). Increasing literature suggests that migration is an important source of stress and can cause continual change in both one’s physical and mental health. In the past 20 years, many researchers repeatedly investigated migrations’ mental health state, however they did not reach consistent conclusions. Some studies found that migrant workers scored in mental problems higher than Chinese adult norm (Jin et al., 1986) and their mental health level is increasing over time, while others presented that migrant workers’ mental health was actually as well as the adult norm. Traditionally, the method of meta-analysis is preformed to integrate these controversies, but these meta-analyses simply compared the statistic results from different studies and neglected the role of their publication years. In order to resolve the controversies, we used the cross-temporal meta-analysis technique to explore the possible change patterns in Chinese migrant workers’ mental health with time. In the present study we collected and analyzed 70 papers collected data from 1995 to 2011, all using the Symptom Checklist 90 (SCL-90) as the measuring tool. Only those that reported the sample size, mean and standard deviation were used and totally 46485 of Chinese migrant workers were included in those papers. Each sample/paper was coded according to the sample size, sampling area, occupation, age and gender, used as independent or control variables. All 9 types of mental problems in SCL-90 were used as dependent variables. The analysis first compared the factorial mean scores of the SCL-90 across data collection years, and then investigated the cross-time changes of different groups separately. Our results showed that the mental health level of Chinese migrant workers increased steadily in the 17 years between 1995 through 2011. Specifically, all 9 types of mental problems correlated with data collection year negatively, the year accounting for 1% to 31% variances of each type of mental problems. The means of 9 types of mental problems decreased in the range between 1% and 39%, among which interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety and paranoid ideation dropped most significantly. There were also significant differences in terms of cross-time changes between groups: migrant workers in the Eastern area, manufacture industry, and female workers showed an increasing trend in mental health, while young workers and male workers exhibited a decrease whereas no change was found for workers in the construction industry. For the first time, the present study integrated different studies and showed that Chinese migrant workers’ mental health was getting better in general. The possible contributions to policy making and societal system construction and implications for future research were discussed.

Key words: migrant workers, SCL-90, mental health, cross-temporal meta-analysis, meta-analysis