The Department for Communities and Local Government have published official guidance on using the indices of deprivation – access the full document here. The annex contains a full list of the data files and supporting documents released for the 2015 Indices. Part of the guidance that might be particularly relevant for users of this site deals with what the IMD2015 can and can’t be used for, and we’ve pasted it below.
What can you use the Index of Multiple Deprivation 2015 for?
Comparing small areas across England
The Index of Multiple Deprivation 2015 uses the same data sources and combines them in the same way for every small area in England. This means you can directly compare the ranks of different small areas in England. If a small area’s rank is closer to 1 than that of another area, it is more deprived.
Identifying the most deprived small areas
You can identify which small areas are amongst the most deprived in England using the published deciles, for example, to show which areas are amongst the 10 per cent or 20 per cent most deprived small areas nationally. You can also apply different cut points to the ranks to identify, for example, the 1 per cent or 5 per cent most deprived small areas nationally.
Exploring the domains (or types) of deprivation
You can look at the domain indices to explore which types of deprivation, e.g. income or health, are more prominent within areas or to focus on particular types of deprivation and explore how areas rank on these.
Comparing larger areas e.g. local authorities
A range of summary measures highlighting different aspects of deprivation are provided for larger areas, including local authority districts. Because patterns of deprivation across larger areas can be complex, there is no single summary measure that is the ‘best’ measure. Comparison of the different measures is needed to give a fuller description of deprivation for larger areas.
You can find out more in section 3.3 of the Research Report.
Looking at changes in relative deprivation between versions (i.e. changes in ranks)
All of the Indices of Deprivation measure relative deprivation at small area level as accurately as possible, but they are not designed to provide ‘backwards’ comparability with previous versions of the Indices (2010, 2007, 2004 and 2000). However, because there is a broadly consistent methodology between the Indices of Deprivation 2015 and previous versions, you can compare the rankings as determined at the relevant time point by each of the versions.
When looking at changes in deprivation between the Indices of Deprivation 2015 and previous versions, users should therefore be aware that changes can only be described in relative terms, for example, the extent to which an area has changed rank or decile of deprivation.
For example, an area can be said to have become more deprived relative to other areas if it was within the most deprived 20 per cent of areas nationally according to the 2010 Index of Multiple Deprivation but within the most deprived 10 per cent according to the 2015 Index. However, it would not necessarily be correct to state that the level of deprivation in the area has increased on some absolute scale, as it may be the case that all areas had improved, but that this area had improved more slowly than other areas and so been ‘overtaken’ by those areas.
You can find out more in section 3.4 of the Research Report.
What can’t you use the Index of Multiple Deprivation 2015 for?
Quantifying how deprived a small area is
The Index of Multiple Deprivation is a relative measure of deprivation. This means it can tell you if one area is more deprived than another but not by how much. For example, a small area with a rank of 1,000 is not half as deprived as a place with a rank of 500.
Identifying deprived people
The Index of Multiple Deprivation measures relative deprivation in an area and is suitable for use where deprivation is concentrated in small areas. Within every area there will be individuals who are deprived and individuals who are not. The Index is not a suitable tool for targeting individuals.
Saying how affluent a place is
The Index of Multiple Deprivation is designed to identify aspects of deprivation, not affluence. For example, the measure of income deprivation is concerned with people on low incomes who are in receipt of benefits and tax credits. An area with a relatively small proportion of people (or indeed no people) on low incomes may also have relatively few or no people on high incomes. Such an area may be ranked among the least deprived in the country, but it is not necessarily among the most affluent.
Comparing with small areas in other UK countries
Each country in the UK produces its own version of the Index of Multiple Deprivation using similar methodologies. However differences in the indicators used, the time periods covered and the sizes of their small areas mean that it is not possible to make direct comparisons between these indices.
The Office for National Statistics provides some guidance on how to make some comparisons across the four countries’ indices:
Measuring real change in deprivation over time
As explained above, one can compare the rankings as determined at the relevant time point by each version of the Indices of Deprivation. But the Indices are not designed to provide ‘backwards’ comparability with previous versions so these should not be used as a time series. Changes between versions of the Indices which limit the ability to make comparisons over time are described in Section 3.4 of the Research Report.