The Survey of Personal Incomes (SPI) is based on information held by HM Revenue and Customs tax offices on individuals who could be liable to UK income tax. It is carried out annually by HMRC and covers income assessable to tax for each tax year. Not all of them are taxpayers because the operation of personal reliefs and allowances may remove them from liability. Where income exceeds the threshold for operation of Pay-As-You-Earn (PAYE), the survey provides the most comprehensive and accurate official source of data on personal incomes. The SPI is compiled to provide a quantified evidence base from which to cost proposed changes to tax rates, personal allowances and other tax reliefs for Treasury Ministers. It is used to inform policy decisions within HMRC and the Treasury, as well as for tax modelling and forecasting purposes. In addition, it is used to provide summary information for the National Accounts that are prepared by the Office for National Statistics. Finally, it is used to provide information to Members of Parliament, other Government Departments, companies, organisation and individuals. The UK Data Archive currently holds the Public Use Tape (PUT) data for 1985-86 and 1995-96 onwards (data for 2008-09 is currently unavailable). For further details of sampling and coverage criteria, see documentation. Further information about the SPI, including income tax and personal incomes statistics, is available on the GOV.UK Statistics about personal incomes webpage. Latest edition informationFor the second edition (July 2025), a new version of the data file was supplied. Previously, an error had been identified where the indicator 'SEINC_NUM', which flags self-employed individuals, had incorrectly identified around 6,000 sample cases as self-employed. This issue has been fixed in the new version. The issue did not affect income amounts as the incorrectly identified cases had no income from self-employment, nor does it affect published statistics in the Personal Incomes Statistics Series based on the SPI for 2016-17. Other years are not affected.