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Background and Methodology

SIMD

Overview

This websection provides users with further information on the background, methodology and development of the Scottish Index of Multiple Deprivation.

Background

The Scottish Index of Multiple Deprivation (SIMD) 2012 identifies small area concentrations of multiple deprivation across all of Scotland in a fair way.

SIMD 2012 is an update with improvements on the SIMD 2009 and uses the same geographical base (datazones) as previous versions of the SIMD. Due to improvements to indicators and methodology, the overall SIMD 2012 and most domains are not directly comparable in absolute terms with those in the SIMD 2009. However there does still remain a strong correlation between SIMD 2009 and SIMD 2012.

The SIMD provides a relative measure of deprivation which means that the main output from SIMD - the SIMD ranks - can be used to compare data zones by providing a relative ranking from most deprived (rank 1) to least deprived (rank 6,505). The SIMD cannot be used to determine 'how much' more deprived one data zone is than another e.g. it is not possible to say that data zone X, ranked 50, is twice as deprived as data zone Y, ranked 100.

The SIMD can be used to identify Scotland's most deprived small areas on the overall index and each individual domain, commonly by applying a cut off such as 10%, 15% or 20%. The cut off should be informed by whether it aims to target areas with the very highest concentrations of deprivation or to be wider ranging.

All versions of the SIMD - SIMD 2012, SIMD 2009, SIMD 2006 and SIMD 2004 - are heavily based on the methodology developed by the Social Disadvantage Research Centre at the University of Oxford.

In developing an area-based measure of deprivation, the Scottish Index of Multiple Deprivation was the Scottish Executive's response to the August 2003 report 'Measuring Deprivation in Scotland : Developing a Long-Term Strategy'.

The final report and the Scottish Executive response are available here:

Measuring Deprivation in Scotland : Developing a Long-Term Strategy and Scottish Executive response

Methodology

The Scottish Index of Multiple Deprivation 2012 combines 38 indicators across 7 domains, namely: income, employment, health, education, skills and training, housing, geographic access and crime.

The overall index is a weighted sum of the seven domain scores. The weighting for each domain is based on the relative importance of the domain in measuring multiple deprivation, the robustness of the data and the time lag between data collection and the production of the SIMD.

Prior to weighting, the domains are standardised by ranking the scores. The ranks then undergo a statistical transformation to avoid high ranks in one domain 'cancelling out' low ranks in another. The domain weightings used in SIMD 2012, expressed as a % of the overall weight are: current income (28%), employment (28%), health (14%), education (14%), geographic access (9%), crime (5%) and housing (2%).

Decisions on changes to the methodology used to create the SIMD, and the indicators included in it, are made in conjunction with data providers and the ScotStat Measuring Deprivation Advisory Group (MDAG).

Full technical details on the methodology and construction of each indicator in the SIMD 2012 are available in the Technical Notes published here: SIMD 2012 Technical Notes

Alongside the Technical Notes there are various papers relating to methodology which are categorised below.

General

Geography

Change Over Time

  • Change over time guidance paper - this paper gives guidance on how to carry out change over time analysis. Whilst there have been changes to the SIMD methodology and indicators used over the three versions of the SIMD it is still possible to look at change over time though care needs to be taken because of the changes.

Employment

Income

  • Impact of tax credit data - this paper looks at the impact of including tax credit data in the Income domain. The figures presented here are based on 2008 benefits data (using 2007 data to identify children in benefit households) as used in SIMD 2009, with and without 2006 tax credit data.

Health

  • Analysis of indicator code change - this paper analyses the impact on the overall Health domain to assist users in understanding the comparability between the SIMD 2006 health domain and that used in SIMD 2009.

Geographic Access