The data quest

Alex Wilson, our data officer, explains how she went about finding relevant, small scale geographical data about migration and change for the Communities up Close project.

The top two questions on my mind as I started to research potential data which would tell us about migration and change in the Yorkshire and Humber region were ‘how up to date is the data?’ and ‘what size geography is it available by? – the smaller the better.’

The ONS [Office for National Statistics] has helpfully divided the UK into areas for the reporting of statistics. These are called output areas [OAs], lower layer super output areas [LSOAs] and middle layer super output areas [MSOAs]. The table below outlines their sizes in terms of population and number of households. You can learn more about them on the census geography page on the ONS website  They are areas which are made up of similar populations and number of households, as a result they tend to be smaller in area in densely populated city or town centres and quite big in sparser populated areas. Every local authority area is split into MSOAs, the MSOAs are split into LSOAs and the LSOAs are split into OAs. All output areas fit perfectly into local authority districts. Data which is available by OA makes me happy as it can tell us a lot about different areas.

Geography Minimum population Maximum population Minimum number of households Maximum number of households
 OA  100  625  40  250
 LSOA  1,000  3,000  400  1,200
 MSOA  5,000  15,000  2,000  6,000






Initially I was looking for data that would give us an idea about the migration to different areas and also data that would tell us a bit about the area, is it affluent or deprived, what sort of jobs people have.

My first port of call for this data threw up a trade-off we would have to make between these 2 criteria:

  • National Insurance number [NINO] data is the most recent and up to date data available which tells us about newcomers to an area. The NINO data is based on National Insurance numbers registered to adult overseas nationals entering the UK and is available to download from the DWP stat-xplore website  However this data is only available by MSOA.
  • Census data however, is available as small as OA but the last one was in 2011 so is more out of date. To add to this the OA boundaries were updated/redrawn between the 2001 Census and the 2011 Census which meant a lot of work was needed to prepare the Census data from 2001 so we could compare it to 2011.

We decided that I would collate all available data by MSOA and support this where possible with data available by smaller geographies.

I did work with these datasets to show the change between different years and also plotted the data against mid-year population estimates to show what percentage of the population were non UK born and how that had changed over time. To tackle the issue of the outdated Census data I downloaded NINO data from 2002 [the earliest data available] and 2011 to reflect the [almost] same time period as the Census and compare them. I downloaded several other years of data so that we could track the change over different time periods, such as the EU accession in 2004.

Census data is available to download from the ONS Nomis website  I used two datasets to tell me about migration, these were Country of birth and Ethnicity data. Although these datasets are not recent, the nature of them tells us about areas that have had long term migration for several generations. I did similar calculations with this data as with the NINO data, plotting it against the population of the area at the time, to find out the percentage share of the population who were non UK born, or who were non-White British, as an indicator of diversity and a much longer-term influence of migration on the population profile.

Other contextual data which proved valuable from the Census was the 2011 residential-based area classifications. Area classifications for Great Britain have been produced after every census since 1971 and as of the 2001 Census, they have been extended to cover the whole UK. Using socio-economic and demographic data from each census, they aim to identify areas of the country with similar characteristics. These are available to download by output area, the data and more supporting information can be found on the ONS website’s ‘2011 residential-based area classifications’ page. They consist of ‘Supergroups’ divided into categories like ‘Hard-Pressed Living’, ‘Suburbanites’ and ‘Rural Residents’, which are then in turn separated into ‘Groups’ such as ‘Farming Communities’ and ‘Industrious Communities’ and then further split into ‘Subgroups’ with descriptions including ‘Self-sufficient retirement’, ‘Families in terraces and flats’ and ‘Inner City Ethnic Mix’.

I used data from the Index of Multiple Deprivation [IMD] as another way to understand the makeup of small areas. The English indices of deprivation measure relative deprivation in LSOAs. The IMD is the most widely used of these indices. I used this data in its raw format as well as using averaged data to illustrate the IMD at MSOA level and also ranked each MSOA within each local authority and within the region. This data came from the website's 'English indices of deprivation 2019' page

The best quality data I used was, without doubt, the Census data - it told me just about everything I wanted to know and by the smallest geographical areas, the only problem was that it was nine years out of date as this project came to an end. The redrawing of the output areas caused me problems which were long and a tad tedious to overcome. This wasn’t helped by the NINO data only becoming available by 2011 MSOAs several months into the project, which meant almost all of the historical NINO data I wanted to use had to be manually prepared into 2011 MSOAs before I could do anything with it.

My advice to anyone undertaking a similar task would be wait until 2021 and then use all that lovely up to date Census data, in the meantime you can ensure you have a computer capable of running ArcMap, perfect your Excel skills and knowledge and a make sure you have a big monitor for all those massive spreadsheets and maps!


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Page last updated: 28/08/2020 07:18:59

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