Locrating's catchment areas explained
Using data that has been provided by the Department of Education and the Office for National Statistics, we have created catchment area indicators for schools in England. By explaining what we have done and how, this post allows you to interpret our catchment maps.
We have two styles of catchment area indicator that can be used either individually or together; summary circles show where the most recent intake of pupils live, whilst detailed catchment breakdowns allow you to look at historical catchment areas and even view areas relating to specific year groups only.
Step 1: Find the right pupilsThe first step is to identify the latest intake of pupils for each school, as these are the ones we are most interested in. For primary schools this is typically reception year pupils and for secondary schools this is typically year 7 pupils.
Our logic ensures that the correct group of children is selected for each school. Where a school is an all through school (i.e. both primary and secondary) we look at the most recent primary age intake. We also ensure that we don’t include children who are looked after or have special educational needs; as they often get priority over other pupils.
Step 2: Work out where these pupils liveOnce we have identified the group of children we are most interested in, we can analyse the data and work out where they live. The diagram below shows an example distribution of reception year pupils who are attending a primary school. For schools that admit based on distance you’ll typically see them distributed fairly evenly around the school.
Step 3: Identify where most of the children liveNext, we apply some mathematics to these locations to work out a radius around each school that contains most of the pupils; by most we mean around 70%. This is the area of highest pupil concentration and an area likely to include future pupils. Where a school admits based on distance, when living in this area you will have a good chance of success for entry into the school.
Step 4: Identify where almost all the children liveWe apply some further mathematics to work out where approximately 80% of the pupils live. Where a school admits based on distance, when living in this area you will have a chance of success for entry into the school, but less so that being in the green area.
Step 5: Identify the furthest children and remove outliersLastly, we shade a circle containing 90% of the children. We drop the furthest 10% because we often find some huge numbers in this group that can skew everything. By removing these outliers from the data, e.g. pupils who were perhaps unusually lucky to get an offer or those who were admitted based on a criteria other than distance, we find the catchment indicator is much more realistic for normal circumstances. Where a school admits based on distance, when living in this area you will have a chance of success for entry into the school, but less so that being in the green or yellow area. It should be noted that you have a chance even when living outside this area as catchments can, and do, vary from one year to the next. We encourage you to read the caveats section below and our catchment area myths blog post.
Step 6: Lower output areasOur second type of catchment area uses Lower Layer Super Output Areas (LSOA); this sounds complicated, but is actually quite simple. A LSOA is an area on a map, a bit like a postcode, which has been automatically generated by the Government to be as consistent in population size as possible, typically around 1,500 people. So, they are larger in rural areas and smaller in more densely populated areas.
By default we shade the areas containing the most recent intake of pupils, as in step 1, but using the catchment area menu options you can chose to change the academic year (look back in time) and also the year group of the pupils included.
These shaded areas are interesting as they provide some insight into slightly more unusual factors affecting the catchment area, such as a local authority boundary or preferential area. If you see consistently year after year certain areas shaded and others not, whilst they the same distance from the school, then it is likely there is some area preference in the schools admission policies. We advise you speak to the school to find out more information on this.
The past does not necessary predict the future. Catchments can, and do, vary from one year to the next. We encourage you to read our catchment area myths blog post for further information on this. Whilst out catchment area guides provide valuable insight, we always advise you speak to the school admissions team.
Important CaveatsThe past does not necessary predict the future. Catchments can, and do, vary from one year to the next. We encourage you to read our catchment area myths blog post.
Not all schools admit by distance alone, the above does not take into account policies such as priority on ability (e.g. grammar), faith, siblings, children of staff or lottery systems. Bulge years will also make catchment areas larger in certain years. Out catchment area guides provide valuable insight but we always advise you speak to the school admissions team.
The small print
This work was produced using statistical data from the Office for National Statistics. The use of the ONS statistical data in this work does not imply the endorsement of the ONS in relation to the interpretation or analysis of the statistical data. This work uses research datasets which may not exactly reproduce National Statistics aggregates.
This data is provided for informational purposes only and we do not accept any liability for decisions based on this data. Past admissions are no guarantee of future admissions, we advise you to always check with the school.
Author: Lewis Tandy