Survey under-coverage of top incomes leads to bias in survey-based estimates of overall income inequality. Using income tax record data in combination with survey data is a potential approach to address the problem; we consider here the UK's pioneering "SPI adjustment" method that implements...

Estimates of UK income inequality trends differ substantially according to whether estimates are based on household survey data (used for official statistics) or tax return data (used in the top incomes literature). We reconcile differences in variable definitions and combine survey and tax...