Primary (key stage 2) league tables

Primary league tables show the results of exams sat in year 6 when pupils are 11 years old (otherwise known as "Key Stage 2"). Our data is from exams taken in 2008. 2009 data at school level is not released until early 2010.
Pupils currently sit exams in 3 broad subject areas: English, Mathematics and Science.
Within each subject there is a level that pupils are expected to acheive (Known as Level 4) and a level that signifies achievement above the expected level (Level 5).
 
"Pass" indicates the percentage of pupils within the school aggregated across the 3 subjects that have acheived the expected level (Level 4). So, if 70% acheived Level 4 in English, 75% in Maths and 75% in Science, this would result in a score of 70 + 75 + 75 = 220. This is a good measure of a school's ability to get a large proportion of pupils up to basic levels of education at age 11, but may not show how well a school develops brighter pupils.
 
"Merit" indicates the percentage of pupils within the school aggregated across the 3 subjects that have acheived the advanced level (Level 5). This is a good measure of a school's ability to develop brighter pupils and achieve excellent performance, although may not show how well a school develops all it's pupils.
 
"Average Point score" is the average score acheived per pupil across all of these subjects. This is the best single measure of a school's academic performance at age 11.
 
"Contextual Value Added" or "CVA" is a measure of the school's performance versus the starting point of pupils at age 7 at that school. This measure is important because schools may have very different starting points (a particular issue with many London schools, for example, is the lack of English language knowledge of many pupils at an early age), which may greatly affect subsequent exam results.
The measure helps distinguish between schools that do well because they have an advantaged intake, from those that do well because they add value to their pupils. A score of 100 indicates that pupils achieve in line with their starting point. Above 100 suggests pupils acheive beyond what would be predicted from their starting point, below suggests that pupils relative performance at age 11 is below their starting point.