Sometimes more equal than others: how health inequalities depend on the choice of welfare indicator.

In recent years, a large body of empirical work has focused on measuring and explaining socio-economic inequalities in health outcomes and health service use. In any effort to address these questions, analysts must confront the issue of how to measure socioeconomic status. In developing countries, socioeconomic status has typically been measured by per capita consumption or an asset index. Currently, there is only limited information on how the choice of welfare indicators affect the analysis of health inequalities and the incidence of public spending. The purpose of this paper is to illustrate the potential sensitivity of the analysis of health related inequalities to how socioeconomic status is measured. Using data from Mozambique, the paper focuses on five key health service indicators, and tests whether measured inequality (concentration index) in health service utilization differs depending on the choice of welfare indicator. The paper shows that, at least in some contexts, the choice of welfare indicator can have a large and significant impact on measured inequality in utilization of health services. In consequence, we can reach very different conclusions about the 'same' issue depending on how we define socioeconomic status. The paper also provides some tentative conclusions about why and in what contexts health inequalities can be sensitive to the choice of living standards measure. The results call for more clarity and care in the analysis of health related inequalities, and for explicit recognition of the potential sensitivity of findings to the choice of welfare measure. The results also point at the need for more careful research on how different dimensions of SES are related, and on the pathways by which the respective different dimensions impact on health related variables. Copyright 2005 John Wiley & Sons, Ltd.