Health insurance market and travel for health purposes: Panel GMM analyses

The status of insurance ownership or lack of insurance significantly shapes individuals' healthcare access strategies and their health-related travel (HRT) decisions. This study examines the effect of private health insurance ownership (PHI) on HRT using panel data from 22 countries over the period 2010-2022. HRT is measured as the share of health-related travel expenditures in total service imports, while PHI represents the proportion of individuals who own private health insurance. Control variables in the model include income (INCOME), price levels (PRICE), healthcare quality (HEALTH_QUALITY), tourism (TOURISM), and the type of health system (SYSTEM). The estimation method employed is the Arellano-Bover/Blundell-Bond System Generalized Method of Moments (System GMM). The lagged dependent variable SAS(-1) is positive and highly significant in all models, indicating that HRT expenditures are sensitive to their past values. The PRICE variable shows mostly positive coefficients but limited statistical significance, whereas income variables are largely statistically insignificant. Healthcare quality indicators (BEDSPER1000, DOCTORSPER1000) display limited and inconsistent effects. When examining the tourism variables, the proportion of international travelers in the population (PITP) was found to be insignificant, whereas the ratio of tourism expenditures to GDP (RTG) exhibited significant and positive effects on HRT. Dummy variables representing health system types (BISMARCK and BEVERIDGE) are mostly insignificant, suggesting that structural differences in health systems do not meaningfully differentiate HRT outcomes. The PHI variable consistently shows a negative effect across all models and is statistically significant in 19 out of 24 models. This finding indicates that increased private health insurance ownership encourages individuals to utilize domestic healthcare services, thereby reducing SAS expenditures abroad. In conclusion, private health insurance ownership emerges as an important determinant of individuals' HRT decisions, whereas other factors such as income, price, healthcare quality, and health system type demonstrate limited or inconsistent effects. Tourism expenditures, on the other hand, play a strong and significant supporting role in influencing HRT.