What do we mean by value added?
Some pupils will find it particularly difficult to reach the level expected for their age in assessment tests. It may be, for example, that they have significant special educational needs (SEN). But all pupils are capable of making progress and it is important that schools are given recognition for the work that they do with their pupils.
We measure the progress that individual pupils have made between tests when they are in Year 6 (KS2), generally aged 11, and tests when they are in Year 9 (KS3) and generally aged 14. We call this the value added measure. Value added measures are intended to allow fairer comparisons between schools with different pupil intakes.
For example, school A might show higher percentages of pupils achieving Level 5 or above than school B. But school A's pupils may have done far better in their KS2 tests than school B's. For the value added measure, each school's pupils are compared individually with other pupils with similar KS2 test results. If they do better than the median - or middle - performance of those other pupils in their KS3 tests, the value added will be positive; if less well than those other pupils, it will be negative. All the individual pupil scores, positive and negative, are added together to form the school's value added measure.
If school A's pupils generally made less progress than the average for pupils with similar KS2 results, and school B's pupils generally made more progress than the average for pupils with similar KS2 results, then school B will have higher value added than school A, even though its percentage achieving Level 5 or above at KS3 is lower.
Value added measure
We base each pupil's value added score on a comparison between their KS3 performance and the median - or middle - performance of other pupils with the same or similar results at KS2. The individual pupil scores are averaged to produce the school level VA measure. This number is presented as a number based around 100. This indicates the value the school has added on average for its pupils.
A more detailed explanation of how value added measures are calculated, for a pupil and a school, can be found in the Value Added Technical Information section on the website.
Interpretation of a school's value added measure
The value added scores are shown as a measure based around 100. Measures above 100 represent schools where pupils on average made more progress than similar pupils nationally, while measures below 100 represent schools where pupils made less progress.
For KS2 to KS3 value added, a measure of 101 means that on average each of the school's pupils made one term's more progress between KS2 and KS3 than the median - or middle value - for pupils with similar KS2 attainment. A score of 99 means that the school's pupils made a term's less progress.
What a school's value added measure tells you
| The value added measure gives the best indication in these Tables of schools' overall effectiveness. But the significance that can be attached to any particular school's value added measure depends, among other things, on the number of pupils included in the value added calculation. The smaller the number of pupils, the less confidence can be placed on the value added measure as an indicator of whether the effectiveness of a school is significantly above or below average. |
Mainstream Schools
As a guide, at KS2 to KS3, for schools with 50 or more pupils in the value added measure, measures of 98.9 to 100.7 represent broadly average performance, while for schools with 100+ pupils, measures of 99.2 to 100.4 are broadly average.
When comparing the measures for two schools with cohorts of about 50 pupils, differences of up to 1.2 should not be regarded as significant, while for schools with about 100 pupils, differences up to 0.9 should not be regarded as significant.
Special Schools
Particular care should be taken with the results for special schools and other schools where cohort sizes are small. For example, for special schools with 10 pupils included in the value added measure, only measures of below 99.0 or above 102.3 are likely to be significantly different from the average.
Value Added Profiles
The table below shows how the value added measure for a school compares to other schools nationally.
| Key Stage 2 to Key Stage 3 Value Added Measure | |
| Profiles | Percentiles | 103.1 and above | Top 5% of schools nationally |
| 100.9 to 103.0 | Next 20% of schools nationally |
| 100.3 to 100.8 | Next 15% of schools nationally |
| 99.7 to 100.2 | Middle 20% of schools nationally |
| 99.1 to 99.6 | Next 15% of schools nationally |
| 97.8 to 99.0 | Next 20% of schools nationally |
| 97.7 and below | Bottom 5% of schools nationally |
Coverage
The coverage column shows the percentage of pupils eligible for KS3 assessment included in the value added calculation. This gives some indication of schools where the value added measure may be unrepresentative. A low percentage means that information was not available to calculate the value added scores of many of the school's pupils, and so these pupils could not be included in the school value added calculation. Where coverage is less than 50%, the value added measure has not been published.
Future developments to value added measures
Currently, the value added (VA) measures used in the Tables take account of individual pupils' prior attainment in comparing school outcomes. The Department is committed to implementing a more sophisticated VA methodology, and is developing a Key Stage 2-3 Contextual Value Added (CVA) measure which will, if successful, be introduced in the 2007 Secondary School (KS3) Tables. This methodology is very similar to that introduced into the Key Stage 4 (KS4) Tables' this year. More details can be found at http://www.dcsf.gov.uk/performancetables
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