Economic Growth and Income Inequality

Economic Growth and Income Inequality

Introduction

The central theme of our presentation is the character and causes of long term changes in the personal distribution of income.

Five specifications may be listed. First, the units for which incomes are recorded and grouped should be family-expenditure units, properly adjusted for the number of persons in each-rather than income recipients for whom the relations between receipt and use of income can be widely diverse. Second, the distribution should be complete, i.e., should cover all units in a country rather than a segment either at the upper or lower tail. Third, if possible we should segregate the units whose main income earners are either still in the learning or already in the retired stages of their life cycle-to avoid complicating the picture by including incomes not associated with full-time, full-fledged participation in economic activity. Fourth, income should be defined as it is now for national income in this country, i.e., received by individuals, including income in kind, before and after direct taxes, excluding capital gains. Fifth, the units should be grouped by secular levels of income, free of cyclical and other transient disturbances.

For such a distribution of mature expenditure units by secular levels of income per capita, we should measure shares of some fixed ordinal groups-percentiles, deciles, quintiles, etc. In the underlying array the units should be classified by average income levels for a sufficiently long span so that they form income-status groups-say a generation or about 25 years. Within such a period, even when classified by secular income levels, units may shift from one ordinal group to another. Therefore, it would be necessary and useful to study separately the relative share of units that, throughout the generation period of reference, were continuously within a specific ordinal group, and the share of the units that moved into that specific group; and this should be done...