Inequality and two decades of British tax and benefit reform

Microsimulation methods are used to identify the contribution of tax and benefit reforms to the significant growth in UK income inequality since 1979. The total effect turns out to depend crucially on the counterfactual against which the reforms are assessed: compared with the alternative of pure price-indexation, the total effect of reform is small; by contrast, compared with a counterfactual in which benefits rose in line with national income (historically the case before 1979), the effect is substantial - approximately half the total rise in income inequality is explained. The impact of reforms on inequality has varied significantly over time: income tax cuts in the late 1970s and late 1980s increased inequality; direct tax rises in the early 1980s and 1990s, together with increases in means-tested benefits in the late 1990s, reduced it. The robustness of the results to sampling variation and to the measure of inequality used is also investigated.