School banding: Ranking within local authority

All secondary schools in Wales have been given a score and then placed in a banding group of between one and five.

It is an assessment of a school's performance in the academic year 2011-12, with Band 1 the best and Band 5 at the other end of the scale.

The scores were derived by assessing school performance within four broad categories:

• The percentage of pupils achieving five A* to Cs at GCSE including English or Welsh and mathematics

• The best eight GCSEs of pupils

• The performance of pupils at GCSE in English or Welsh and mathematics

• Attendance

Within each category, a school's score is modified to take into account the percentage of pupils eligible for free school meals.

Most of the categories also take into account a school's progress over time, to reward schools that are making improvements in performance.

Schools are scored on 12 separate measures in total, to provide an overall result, although two of the measures only count for half a point score.

BBC Wales has ranked each school by its score within each local authority.