Dependent variables
In this study, health service demand is mainly measured by physician visits and ER utilization. As for physician visits, two outcomes variables are constructed: a binary variable indicating any physician visit, and then positive numbers of physician visits during the previous 12 months. In our data sample, nearly 80% of respondents have visited physicians at least once in the past 12 months. ER utilization is measure by the number of ER visits in the past 12 months, which has a mean of about 0.3 times.