The evolution of UK income inequality: a GB2 distribution perspective

Author: Stephen Jenkins (London Schoof of Economics and Political Science (LSE))
Posted: 17 September 2026

Abstract

This paper fits four-parameter GB2 distributions to UK unit record household survey data for 42 years from 1977 to 2018. Parameter estimates are used to describe key features of the household income distribution and its evolution over time, including inequality. The paper also discusses and illustrates issues of statistical inference and data quality, and the relative goodness of fit of distributions that are special cases of the GB2. Singh-Maddala distributions typically fit better than Dagum distributions, and the two-parameter Fisk distribution fits the UK income distribution well for almost every year in the 2003–2018 period.
JEL codes: C16, C46, D31
Keywords: Income inequality, Generalized Beta distribution of the Second Kind, Singh-Maddala distribution, Dagum distribution