How well does the Scottish Index of Multiple Deprivation identify income and employment deprived individuals across the urban-rural spectrum and between local authorities?

Background: Area-based indices of deprivation are used to identify populations at need, to inform service planning and policy, to rank populations for monitoring trends in inequalities, and to evaluate the impacts of interventions. There is scepticism of the utility of area deprivation indices in rural areas because of the spatial heterogeneity of their populations.

Objective: To compare the sensitivity of the Scottish Index of Multiple Deprivation (SIMD) for detecting income and employment deprived individuals by urban-rural classification and across local authorities.

Study Design: Descriptive analysis of cross-sectional data.

Methods: Data from the 2020 Scottish Index of Multiple Deprivation (SIMD) were used to calculate the number and percentage of income and employment deprived people missed within each of the six-fold urban-rural classification strata and each local authority using areas ranked by the national SIMD, within local authority rankings, and within urban-rural strata rankings, for deprivation thresholds between the 5% most deprived areas and the 30% most deprived areas. The Slope Index of Inequality (SII) and Relative Index of Inequality (RII) were calculated within local authorities and urban-rural classification strata to estimate the concentration of deprivation within ranked data zones.

Results: The number and percentage of income and employment deprived people is higher in urban than rural areas. However, using the national, local authority, and within urban-rural classification strata rankings of SIMD, and under all deprivation thresholds (from the 5%-30% most deprived areas), the percentage of income and employment deprived people missed by targeting the most deprived areas within urban-rural strata is higher in more remote and rural areas, and in island local authorities. The absolute number of income and employment deprived individuals is greater in urban areas across rankings and thresholds.

Conclusion: The SIMD misses a higher percentage of income and employment deprived people in remote, rural and island areas across deprivation thresholds and irrespective of whether national, local or within urban-rural classification strata are used. However, the absolute number of people missed is higher in urban areas.