What does it all mean?
This is the really important question when looking at any data, and particularly data as important as the Scottish Index of Multiple Deprivation. So, how should the patterns we see on the map - and the associated data - be interpreted? In an attempt to answer this question, and several others, I have provided some further information below. This is based upon my understanding of deprivation indices used across the United Kingdom and also on some of my published academic papers. The mapping is based on the relative rank of an area compared to all other Data Zones in Scotland. This helps us understand how areas compare to each other but it doesn't tell us about absolute levels of (e.g.) employment or income. For that you need to look at the domains of the SIMD, which you can find on the new SIMD 2012 portal.
How should we interpret what we see on the map?
From the interactive map it is easy to spot large concentrations of areas with similar deprivation levels. A high percentage of Edinburgh's Data Zones are amongst Scotland's least deprived 20%, whereas a high percentage of Glasgow's Data Zones are amongst Scotland's most deprived 20%. At a very basic level this tells us that there is often a high degree of correlation between areas that are located close to each other. This phenomenon is sometimes referred to in relation to Waldo Tobler's 'First Law of Geography' and of course is hardly surprising. Interpretation of patterns should initially be based on the shading on the map but also by clicking on individual areas to find out more. Only then do we get a more fine-grained picture of an area - but of course the official data are always only part of the story (as Einstein supposedly said, "Not everything that can be counted counts, and not everything that counts can be counted").
Are all the 'poor' people concentrated in 'poor' areas?
When we look at the map and see an area shaded red, it is usually safe to assume that individuals living there will be more deprived than those in other area. At an aggregate level, this is the case but the drawing of boundaries is always somewhat arbitrary and many 'poor' people do not live in 'poor' areas. Conversely, many 'rich' people don't live in 'rich' areas. This may be the exception but if you add up the number of people in each of Scotland's 6,505 Data Zones who have significantly different characteristics from the area they live in then the number is probably not insignificant. Recent research by Peter Matthews at Heriot Watt University highlighted this in relation to approaches to Scottish urban policy. Are all 'poor' people in 'poor' areas? No. Most are, but a significant minority are not. In more technical terms, this relates to the concept of the 'ecological fallacy'.
Is 'deprivation' the same as 'poverty'?
This is a very good question. They are not the same thing but there are major overlaps between the two. Poverty is usually defined in relation to some percentage of national median income, for example: "The usual definition of relative low income are households whose equivalised income before housing costs is below 60% of the median ( i.e. midpoint) income in the U.K. in the same year" - you can read more on this on the Scottish Government web pages. So, poverty is defined by income. Deprivation (as in the SIMD) includes income but it is a much wider measure and also includes employment, health, education, housing, access, and crime. Poverty and deprivation are not the same thing but areas with the highest levels of poverty are most often the most deprived. It would not be technically correct to conflate the two but given the links between income and employment/health/education/housing/access/crime it is safe to assume a strong relationship between the deprivation and poverty.
Is it possible that deprivation can be 'hidden' in some places?
This is a very important question and and is discussed on the Scottish Government web pages in relation to the Experience of Rural Poverty in Scotland. There is a worry that the SIMD does not adequately capture rural poverty and this might be because small pockets of rural poverty are within much larger Data Zones which are, on aggregate, not very deprived. If you look at some of the very large Data Zones in the Highlands you can see how this could occur. The SIMD (similar to indices used elsewhere in the UK) has been accused of being urban-centric so the Scottish Government provide a guidance FAQ page on this matter.
Have things changed much over time?
One of the defining characteristics of spatial patterns of deprivation is how little they change over time. I wrote about this recently in a paper in Local Economy and this made me think about what was the biggest problem - concentrated deprivation or the fact that things never seem to change much over time. Both are actually very important but it seems to me that more attention is paid to the former than the latter, and particularly so when each update of the SIMD comes out. That's why I've included the relative rank for each SIMD since 2004 in my pop-up charts on the map. Some areas do change significantly over time, but the vast majority don't. The biggest changes usually occur when some major physical changes have impacted an area - such as demolition of Glasgow tower blocks.
What is the significance of using 20% cut-offs (or 15%, or 10% or 5%)?
I have coloured the map using 20% cut offs so that each colour includes 1,301 Data Zones (out of 6,505). Many uses of the SIMD focus on the most deprived 15% so if you want to find out if an area is within the 15% most deprived in Scotland all you have to do is click on an area and if it is ranked from 1 to 976 then it is within that category. The significance of different cut-offs is that policies tend to focus on the most deprived 5%, 10%, 15%, 20% and so on. These are in some ways arbitrary cut-offs but for area-based policy purposes it is often necessary to say which areas are included and which are not. The SIMD is the main way in which this is done. For more information on this issue, and others, see the SIMD FAQ page on the Scottish Government website.