Longitudinal analysis of income-related health inequality.

This paper considers the characterisation and measurement of income-related health inequality using longitudinal data. The paper elucidates the nature of the Jones and López Nicolás (2004) index of "health-related income mobility" and explains the negative values of the index that have been reported in all the empirical applications to date. The paper further presents an alternative approach to the analysis of longitudinal data that brings out complementary aspects of the evolution of income-related health inequalities over time. In particular, we propose a new index of "income-related health mobility" that measures whether the pattern of health changes is biased in favour of those with initially high or low incomes. We illustrate our work by investigating mobility in the General Health Questionnaire measure of psychological well-being over the first nine waves of the British Household Panel Survey from 1991 to 1999.