Sources of specialist physician fee variation: evidence from Australian health insurance claims data

This study explores the variation in specialist physician fees and examines whether the variation can be attributed to patient risk factors, variation between physicians, medical specialties, or other factors. We use health insurance claims data from a large private health insurer in Australia. Although Australia has a publicly funded health system that provides universal health coverage, about 44 % of the population holds private health insurance. Specialist physician fees in the private sector are unregulated; physicians can charge any price they want, subject to market forces. We examine the variation in fees using two price measures: total fees charged and out-of- pocket payments. We follow a two-stage method of removing the influence of patient risk factors by computing risk-adjusted prices at patient-level, and aggregating the adjusted prices over all claims made by each physician to arrive at physician-level average prices. In the second stage, we use variance-component models to analyse the variation in the physician-level average prices. We find that patient risk factors account for a small portion of the variance in fees and out-of-pocket payments. Physician-specific variation accounts for the bulk of the vari- ance. The results underscore the importance of understanding physician characteristics in formulating policy efforts to reduce fee variation.