Every year the government provides data on attainment, progress and absence in all of England's primary schools. Media organisations, including the BBC, then use the information to compile so-called league tables. This guide explains the measures used, and how the information is displayed in our tables.
KEY STAGE 2 (KS2) SATS
Sats are the popular name given to the national curriculum tests that pupils are required to sit in the final year of primary school, at the age of 10 or 11. The attainment data in the tables comes from these tests, which are marked externally.
In previous years pupils have taken Sats in science as well as maths and English, but the science assessments were dropped in 2009. The figures in the tables relate to all local authority-maintained mainstream primary and middle schools with pupils eligible for assessment at the time of the tests in English and maths in May 2010. They do not include special schools, pupil referral units, hospital schools or private schools.
In 2010, about a quarter of schools boycotted Sats. This was because they objected to the use of the test results in league tables and also argued that the system forces teachers to "teach to the test" too much.
Schools that boycotted the tests are labelled with the word "boycott" in their data fields. When the tables are ranked, they will appear at the bottom of the table. This does not indicate that they performed less well than other schools - just that there is no data available.
Most of these schools will, however, have provided data from assessments carried out by teachers. This data can be seen on the page published by the government for each individual school, which you can view by clicking on the school's name in the table.
Level 4 is the standard that most children in this age group are expected to attain in their Sats tests. The proportion of children in a school reaching this target in both maths and English has long been used as a government benchmark, and it is the first measure displayed in the tables.
Under Labour, schools where less than 30% of children attained Level 4 were considered underperforming. The Coalition government is raising the "floor target" to 35%, but is now going to exclude schools where pupils are making sufficient progress, even if their attainment remains low.
Pupils gaining Level 5 in their maths and English Sats are considered to have exceeded expectations for their age. The government gives figures for the proportion of pupils in each school attaining Level 5 in maths and English separately. These are not shown in the BBC's tables, but can be seen in the government's school pages, which you can visit by clicking on the school's name in the BBC table.
This gives the average points per pupil in the English and maths Sats tests. It involves adding up all the points that pupils achieved in the two subjects, then dividing this by the number of pupils eligible to take the tests. The maximum is 33.
This measure enables more detailed comparison between schools' results than simply comparing Level 4. This is because it reflects the achievements of pupils who did not attain level four but still gained some points, and of pupils who exceeded level four. It is used in the BBC tables as a tie-breaker when schools are ranked on their Level 4 attainment.
This is a measure developed to show how much progress a school's pupils have made, in comparison with others from similar backgrounds in terms of factors outside the school's control, such as deprivation, ethnicity and first language.
A CVA score is worked out for each pupil by comparing their Key Stage 2 performance with that of other pupils from similar backgrounds nationally, who have similar prior attainment at Key Stage 1.
Averaging these individual scores gives a score for the whole school. A formula is then used to convert this to a number based around 100.
According to the Department for Education, a measure of 101 means that, on average, the pupils have achieved one term's more progress than the national average, while a score of 99 means that the school's pupils made a term's less progress.
Schools can be ranked in the BBC tables by their CVA scores, but this gives a broad indication only. The rankings need treating with care. Each score has a "confidence interval" - a range of uncertainty. There is wider uncertainty around smaller schools' scores than larger ones, which means that comparing the scores is not exactly comparing like-with-like.
For various reasons complete "before and after" scores are not available for all pupils. Where the data are missing for 50% or more of those eligible to take the tests, the value added score is not published.
The national curriculum includes levels, which are used to assess what pupils are capable of.
Introduced in 2009, the progress measure shows the proportion of pupils whose attainment rose by at least two national curriculum levels between the end of Key Stage 1 (aged about seven) and the end of Key Stage 2 (10 or 11). For example, a child who was at level two at Key Stage 1, and attained level four at Key Stage 2, would have made the expected progress. All pupils who attained level five in their tests are treated as if they had made the expected progress.
The progress measures are not included in the BBC league tables, but can be seen on the government's pages for each school, and are also used in calculating which schools are below the government's "floor target".
If there is not enough data on a pupil, for example if they have moved schools or recently arrived in the country, it may not be possible for them to be included in the calculation.
The proportion of pupils in any given school included in this calculation is given on the page for that school published by the government.
These are marked by coloured bars which appear in the tables when the columns are sorted. The bar appears above the first school which is either on or below the average.
The letters SS signify a small school, with fewer than 11 pupils eligible to take the tests. They are included in the alphabetical lists for completeness, but no results are published for them so they do not appear in the rankings.
If N/A appears in the results column, this can mean:
- the school is a new school with no eligible pupils
- the school has no pupils at the end of Key Stage 2
- results were not published for the year in question
- test results were unavailable for reasons beyond the school's control
Ministers agree it is unfair for schools to be judged on the results of children who have arrived recently from overseas and whose first language is not English, so the schools can choose to omit these pupils from the eligible number in the performance tables.
Some schools will have improved their performance as a result, although they are not identified in the data.