On the Measurement of Functional Income Distribution

The present paper proposes a theoretical framework to examine the relationship between the functional and personal distribution of income. To this end, it introduces the concept of inequality in income composition. Inequality in income composition is high when two different sources of income are separately earned by the top and the bottom of the income distribution. On the contrary, it is low when each individual has the same population share of the two sources. This article designs an indicator to measure income composition inequality, named income-factor concentration index. The sign of the indicator determines the condition of transmission for the rising share of income from any source to increase overall income inequality. This framework is then applied to several European countries on basis of EU-SILC data.