Impact of Medicare Part D on income-related inequality in drug expenditure

Lead Researcher Email Number Webpage
Professor Philip Clarke View page

Project Details

In this project, we outline the use of inequality measures to evaluate the impact of extending health insurance on income-related inequality in drug expenditure using the example of Medicare Part D in the United States. The Medicare Part D program increased access to prescription medications for Medicare beneficiaries from 2006. We use pooled cross-sectional samples from the Medical Expenditure Panel Survey to estimate income-related inequality in drug expenditures using the concentration index and generalised concentration index. A difference-in-differences analysis is conducted on the inequality in drug expenditures between the elderly (over 65 years) and near-elderly (54-63 years) pre and post the implementation of Medicare Part D to evaluate the effect of the policy on the inequality in public drug expenditures.

This study demonstrates the usefulness of measuring the impact of health system changes on inequalities in health expenditure and provides a guide for future evaluations.


Dr Natalie Carvalho


Professor Joshua Salomon (Harvard)


University of Melbourne

Research Group

Health Economics

School Research Themes

Data science, health metrics and disease modeling

Key Contact

For further information about this research, please contact the research group leader.

Department / Centre

Centre for Health Policy

Unit / Centre

Health Economics