The impact of private hospital insurance on the utilization of hospital care in Australia

We use the Australian National Health Survey to estimate the impact of private hospital insurance on the propensity for hospitalization as a private patient. We account for the potential endogeneity of supplementary private hospital insurance purchases and calculate moral hazard based on a difference-of-means estimator. We decompose the moral hazard estimate into a diversion component that is due to an insurance-induced substitution away from public patient care towards private patient care, and an expansion component that measures a pure insurance-induced increase in the propensity to seek private patient care. Our results suggest that on average, private hospital insurance causes a sizable and significant increase in the likelihood of hospital admission as a private patient. However, there is little evidence of an expansion effect; the treatment effect of private hospital insurance on private patient care is driven almost entirely by the substitution away from public patient care towards private patient care. We discuss the implications for policies that aim to expand supplementary private insurance coverage for the purpose of reducing excess demand on the public healthcare system.