Guide: Secondary league tables

The tables, published annually, are used by many parents as they try to choose schools for their children

School league tables are produced every year from official data published by the government on pupils' achievement in England. This guide explains the measures used and how the information is displayed in the BBC's tables.

GCSE AND EQUIVALENTS

The key government benchmark for secondary schools is the percentage of pupils gaining at least five A*-C GCSEs passes, including English and maths.

As part of the benchmark, vocational qualifications such as BTecs and NVQs, taken in Key Stage 4 by 14- to 16-year-olds, are given equivalent scores to GCSEs and included in the five GCSEs score.

Also, some international GCSEs - but only those accredited by the qualifications watchdog, Ofqual - are included. These can be the preferred choice of some independent schools and had, in past years, seen many leading private schools ranked towards the bottom of the tables.

ENGLISH BACCALAUREATE

This measure, introduced by Education Secretary Michael Gove in 2010, is the proportion of pupils achieving A*-C passes in English, maths, two science subjects, a modern or ancient language, and either history or geography.

While the government plans to award a certificate to pupils achieving this combination of GCSEs, it is not a qualification in its own right. More details about the English baccalaureate can be found here.

VALUE-ADDED

This is a statistical measure designed to show how well a school has helped its pupils progress since they arrived from primary school, taking into account their different starting points. It is calculated by assessing pupils' best eight GCSEs and so covers a range of their achievements.

An average is then calculated to give a score for the school. A score of 1,000 is the national average, so anything above that score is regarded as good.

GCSE AVERAGE POINT SCORE

Each GCSE-level qualification and grade is given a score in points, enabling an average point score per pupil to be calculated for each school.

The points scores can be seen on the government data page for each school. You can view this by clicking on the school's name in the table. This is used in the BBC tables as a tie-break measure for schools scoring the same results at GCSE-level.

A/AS LEVEL POINTS PER PUPIL

This is the average number of points achieved per pupil at A/AS-level.

A/AS LEVEL POINTS PER ENTRY

This is the average number of points achieved per A/AS Level per entry. It is used in the BBC's secondary school tables as a tie-break measure for schools scoring the same on A/AS Level points per pupil.

SCHOOL SIZE

The government does not publish data for schools with fewer than six pupils. These appear in the BBC tables, but SS is displayed in the data fields, and they disappear from the lists when the tables are sorted.

Data for schools where fewer than 30 pupils sat GCSEs is given, but these also disappear from the list when the tables are sorted and in tables showing top and bottom performing schools.

Data for schools where fewer than 10 pupils sat A/AS-levels is also given, but again, these disappear from the list when the tables are sorted and in tables showing top performing schools.

INSTITUTION TYPES

In the name field of the BBC's league tables, schools may be marked as:

• IND - independent/fee-paying school

• SEL - schools which select on the basis of academic ability

• ACC - academy converter school

• AC- sponsored academy school

• SHUT - schools which closed during the academic year

The government's data page for each school provides further information on whether it is a girls', boys' or mixed school, its funding and governance arrangements and any subject specialism.

The tables include schools without sixth forms, schools with sixth forms, and further education colleges that take only 16-18-year-old students. Pupil referral units, hospital schools and unclassified test/exam centres are not included.

N/A - NOT AVAILABLE

If N/A appears in the results column, this can mean:

• The school has no pupils in the relevant age group

• The school has pupils in the Key Stage 4 age group, but did not enter any of them in relevant exams

• The school is independent and is not covered by the measure in question

• Results were not published for the year in question.