Abstract
The National Health Insurance Expenditure has been increased rapidly since the introduction of the separation of prescription and dispensing in 2000, and this trend of rapid growth in overall spendings rate has been observed predominantly among medical practitioners. This study was conducted to investigate the growth rate and distributional changes in private medical practitioners' expenses from 1999 to 2002 and its determinants using the National Health Insurance claims data. The total increasing rate of all medical practitioners' expenditure paid by the National Health Insurance between 1999 and 2002 was $41.71\%$, which exceeding that of general hospitals by $20\%$p. But the income distribution among each practitioner was improved as the changes in Gini coefficient(from 0.40 to 0.38) and decile distribution ratio(from 0.25 to 0.29) during the same period showed. However, this improvement in distributional patterns is not enough since even in 2002 it turned out that the highest $10\%$ income group earned 33times more than the lowest $10\%$ income group did. Also, higher Gini coefficient was observed in larger cities and some department like plastic surgery, obstetrics and gynecology. The major causes of this differentials in medical practitioners' expenses were factors related to medical demand like proportion of old population, residential economic status in a given area. In addition, providers' economic incentives also played an important role in determining their income distribution. The large income differentials among physicians may imply a skewed distribution of patients and thus long waiting time, inefficient utilization of resources and potential inadequate quality of care. In this sense, unreasonable distributional gaps should be reduced, so effective measures as well as ongoing monitoring would be necessary to correct current distributional problems.