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Frequently Asked Questions - Updated 13/05/13



This section contains a number of frequently asked questions (FAQs) about the Scottish Index of Multiple Deprivation.

The questions are grouped by four broad themes:

SIMD Methodology


Does the SIMD take account of the age and sex structure of the datazone population?

Yes, to a certain extent. Each indicator has a population denominator and this is not always the total population. For example, the employment domain denominator is the working age population and the secondary attainment rate uses the population of S4 pupils only.

For some of the indicators (mainly health domain indicators) the rates have been indirectly age-sex standardised - this means that the rate you see at datazone level is the ratio of what you expect to what is observed, given the age and sex structure of the population in that datazone. If the rate is greater than 100, the value is greater than you might expect and if it is lower than 100, it is less than you might expect, based on the national average. The SIMD 2006 technical report provides more information on the process of age-sex standardisation.

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How were the domain weightings decided?

The weights are those used in Scottish Indices of Deprivation (SID) 2003, adjusted to allow the inclusion of the Housing domain in SIMD 2004 and the Crime domain in SIMD 2006. The work by Oxford University's Social Disadvantage Research Centre on SID 2003 concluded that the Income and Employment domains should carry most weight in the overall index. This is partly due to the fact that these domains are more robust and partly since this is in line with the academic literature on deprivation. The weights for the remaining domains were chosen with the criteria that the domains with the most robust indicators should be given the greatest weights. (It is important to note that only indicators which are sufficiently robust are included within the index.)

The weights for SID 2003 were strongly based on academic literature and Oxford University's own research. In particular, they pointed to Townsend's definition of deprivation: 'while people experiencing some forms of deprivation may not all have low income, people experiencing multiple or single but very severe forms of deprivation are in almost every instance likely to have very little income and little or no other resources.' They therefore accorded the Income and Employment domains the highest weights since they saw worklessness as a deprivation in its own right, and not simply a driver for low income.

The choice of weights is a matter of informed judgement. In the final analysis there is no ultimate method by which to measure multiple deprivation, as it is a combination of individual deprivations, measured here in the SIMD  domains. However, the domain weights in the SIMD have been chosen based on those used in SID 2003 which gave due regard to the driving forces behind multiple deprivation, as discussed in the wider academic literature.

All decisions on weightings take place after a sensitivity analysis of the effects of changing the weights and consultation with the ScotStat Measuring Deprivation Advisory Group.

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Has the methodology you use been independently reviewed?

Yes. The University of Glasgow's Robertson Centre for Biostatistics conducted an independent evaluation of the methodology used in the SIMD 2004. They passed the 'health check' on its methodology, although they did produce a series of recommendations to simplify and improve it. The Scottish Government accepted some of these recommendations. The full report by Glasgow University and the Scottish Government's response were published in November 2005 and can be found in the publications section of the SIMD website.

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Who decides how the SIMD is constructed?

Decisions on the methodology used in the SIMD are made independently by Government Statisticians in conjunction with the ScotStat Measuring Deprivation Advisory Group.

In August 2011, the United Kingdom Statistics Authority (UKSA) designated the SIMD as National Statistics, in accordance with the Statistics and Registration Service Act 2007.

This signifies compliance with the Code of Practice for Official Statistics and can be broadly interpreted to mean that the statistics

• meet identified user needs

• are well explained and readily accessible

• are produced according to sound methods, and

• are managed impartially and objectively in the public interest.

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How often is SIMD updated?

The first SIMD was published in 2004, with updates in 2006, 2009, and 2012.

The pattern of a three-year gap between updates would point to the next update being in 2015. We will however consult users on this as there are other issues to be taken into consideration, e.g. availability of 2011 Census data,  re-drawing of datazone boundaries, and changes to the benefits system as a result of welfare reform

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