How well do area-based deprivation indices identify income- and employment-deprived individuals across Great Britain today?

BACKGROUND: Area-based deprivation indices are used in many countries to target interventions and policies to populations with the greatest needs. Analyses of the Carstairs deprivation index applied to postcode sectors in 2001 identified that less than half of all deprived individuals lived in the most deprived areas. OBJECTIVE: This article examines the specificity and sensitivity of deprivation indices across Great Britain in identifying individuals claiming income- and employment-related social security benefits. STUDY DESIGN: This was a descriptive analysis of cross-sectional administrative data. METHODS: The data sets for the 2020 Scottish Index of Multiple Deprivation, Scottish Income and Employment Index, the 2019 English Index of Multiple Deprivation and the 2019 Welsh Index of Multiple Deprivation were obtained. For each data set, small areas were ranked by increasing overall deprivation, and the cumulative proportions of individuals who were income and employment deprived were calculated. Receiver operating characteristic curves were plotted to show the sensitivity and specificity of each index, and the percentages of income- and employment-deprived individuals captured at different overall deprivation thresholds were calculated. RESULTS: Across all indices, the sensitivity and specificity for detecting income- and employment-deprived individuals were low, with less than half living in the most deprived 20% of areas. Between 55% and 62% of income-deprived people and between 56% and 63% of employment-deprived people were missed across the indices at the 20% deprivation threshold. The sensitivity and specificity were slightly higher for income deprivation than employment deprivation across indices and slightly higher for the Scottish Index of Multiple Deprivation and Scottish Income and Employment Index than for the English Index of Multiple Deprivation and Welsh Index of Multiple Deprivation. CONCLUSION: Area-based deprivation measures in Great Britain have limited sensitivity and specificity for identifying individuals who are income or employment deprived. Place-based policies and interventions are unlikely to be effective at reducing inequalities as a result. Creation of individually linked data sets and interventions that recognise the social and economic relationships between social groups are likely to be more effective.