Centre for Assessment
Information about assessment
Testing for value added purposes
One important use of tests in the UK is for assessing ‘value added’ by schools. This is commonly undertaken by secondary schools when a new cohort of pupils joins the school, usually in year 7. This practice is described below as an example of how value added testing works.
The purpose is to establish a baseline against which later performance of this cohort, and hence the progress they have made - the value added by the school - may be judged. Pupils will normally have taken National Curriculum Tests in year 6, towards the end of their primary schooling, but these are not well suited to value added because so many pupils are awarded Level 4. As a result, schools may use other tests, such as the Cognitive Abilities Test (CAT3), at the start of year 7 as a measure of general attainment. Value added can then be calculated using the pupils’ GCSE results at age 16 as the output measure, although it is also possible to look at value added at intermediate points, such as the national curriculum tests taken in year 9, or later points, such as A level in year 13.
The method involves comparing the baseline measure and output measure for each pupil and analysing whether the gain is average, above average or below it. Such analyses usually involve several schools, and are most properly done using 'multi-level modelling'. From this it is possible to compare the value added by the school to the cohort as a whole with average measures of value added. Such analyses can be carried out on overall performance, as well as separately for subjects such as mathematics and English. The school then has a measure of how well it is doing that allows for the attainment level of pupils when they enter the school. This contrasts with the nationally published league tables of schools that do not allow for attainment on entry.
More sophisticated analyses may also involve background variables relating to other influential factors such as social class, English as an additional language, ethnicity and gender. It is a matter of debate whether these can be termed value added analyses.