Guide: Primary league tables 2012

School league tables are produced every year from government data on pupils' academic achievement in England. The tables can be used as a means of informing choices, but do not tell you everything about a school. These are the measures the BBC is using for its primary-school tables this year.

KEY STAGE 2 (KS2) SATS

Sats are the popular name given to the national curriculum tests pupils sit in the final year of primary school. Much of the results data in the tables comes from these externally-marked tests. Children take these tests and teacher assessments in maths, reading and writing in Year 6, when they are aged 10 or 11.

The figures in the tables relate to all local authority-maintained mainstream primary and middle schools. They do not include special schools, pupil referral units, hospital schools or private schools.

% GAINING LEVEL 4 IN MATHS AND ENGLISH

Level 4 is the standard most children are expected to reach in their KS2 Sats tests in Year 6.

Schools are said to be under-performing if fewer than 60% of their children reached Level 4 in maths and English, although the government says it will also take in to account progress being made.

HIGH-ACHIEVING PUPILS

Pupils who gain Level 5 in both their maths and English Sats are considered to have exceeded expectations for their age. They will have reached the level of achievement expected of a 14-year-old - hence the term high-achieving pupils.

The government also gives figures for the proportion of pupils in each school reaching Level 5 in maths and English separately. These can be found on the individual school pages published by the Department for Education (DfE).

VALUE-ADDED SCORE

The value-added measure looks at how much progress pupils have made between the end of Key Stage 1 (infants) and the end of Key Stage 2 (juniors). A school's value-added score helps to identify schools that are helping their pupils make more or less progress than average. The higher the score, the more progress pupils are making.

AVERAGE POINT SCORE

This is the number of average points per pupil in Sats tests in the two core subjects of English and maths. Although it does not appear as a separate column in the main tables, the BBC uses this as a tie-break measure where schools score the same results. It is also used as tie-break measures for BBC tables ranking the best and worst performing schools, the performance of local authorities and the schools where the most pupils attain Level 5. It includes the results of all pupils, not just those gaining Level 4, and is therefore a fuller measure of school attainment.

SMALL SCHOOL

The letters SS signify a small school, with fewer than six pupils eligible to take the tests. They are included in the alphabetical lists for completeness, but no results are published for them.

N/A' - NOT APPLICABLE

If N/A appears in any of the results columns, it can mean a number of things. This includes the school being a new school with no eligible pupils or one with no pupils at the end of Key Stage 2. It can also mean results were not published for the year in question or that test results were unavailable for reasons beyond the school's control. It can also mean that there is a maladministration investigation under way or that parts of the tests were not completed or results submitted.

RECENT ARRIVALS

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.