The Effects of Social Medical Insurance Participation on Migrant Workers in China: Estimation Based on the Propensity Score Matching Approach

The magnitude of migrant workers reached 274 million in 2014. Since the social welfare system of China is locality-based depending on the household registration (hukou) system, migrant workers are excluded from the urban public health service system (1). They are especially vulnerable to three health threats: infectious diseases, maternal health, and occupational diseases and injuries (2). To protect the health security of migrant workers , the Chinese government has implemented the social medical insurance (SMI) which dedicates to incorporate migrant workers into the urban public health system. This system is contributed to both migrant workers and their employers and is committed to protecting migrant workers against health risk (3). The purpose of this study was to examine the effects of SMI on medical service utilization, out-of-pocket cost, and medical reimbursement of migrant workers. Since previous studies have neglected that the characteristics of insured and uninsured migrant workers are not comparable, this research used the propensity score matching (PSM) method to overcome this issue. Data used in this study was from the Rural Urban Migrant in China (RUMiC) survey project which is an international cooperation project initiated by a team of international researchers. The survey was conducted in 15 cities located in 9 different provinces and municipalities of China in 2008 and 2009. Totally, 8446 and 5426 migrant workers were interviewed in 2008 and 2009 respectively. Among all migrant workers, 1422 reported that there were sick or injured during the last three months. In this study, we analyzed medical service utilization, medical reimbursement, and out-of-pocket cost of the 1422 migrant workers. Medical service utilization is measured by asking migrant workers " what did you do when you were sick or injured? " Responses include two categories (1=see a doctor in a medical office, clinic, or hospitals; 0=do nothing or self-medication). Out-of-pocket cost is measured by asking migrant workers " how much did you personally pay? " Medical reimbursement is defined as the difference between gross cost and out-of-pocket cost. Gross cost is measured by asking migrant workers " how much was the total medical expense on the sickness or injury in the last three months? " Social insurance participation is measured by asking migrant workers " did you participate in SMI? " Responses include two options (1=yes; 0=no). Initially, we used demographic characteristics, socioeconomic status, and migration experience of migrant workers as independent variables in the Probit model to estimate