was awarded a point score (so that working towards a level 1 at KS1 is awarded 3
points, and level 4 or more converts to 27 points). The scores for overall reading,
writing and mathematics at KS1, and the scores for English, mathematics and science at
KS2, were then averaged for each pupil. A pupil’s value-added score is calculated by
comparing their KS2 average with the median KS2 score for all pupils with the same
KS1 score. Thus, in mainstream schools, a pupil with an average of level 1 at KS1 (9
points) might be expected to attain an average of level 3 at KS2 (21 points), for
example. The value-added score for each school is the average of the value-added
scores for all pupils meeting the definition above (with 100 added to this average to
eliminate negative values). 100 is near par, and a value-added score between 99.4 and
101.2 is described as ‘broadly average’.
This paper uses the Key Stage 2 (KS2) results for mainstream primary schools in
England in 2005, and their published DfES value-added scores. The re-analysis
presented here is based on all 457 primary schools with complete information in York,
Leeds, and North Yorkshire. Results are presented in scatterplot form, or as Pearson R
correlation co-efficients - which can be squared to give an ‘effect’ size. The approach is
very similar to that used in Gorard (2006c), which demonstrated that value-added
scores in secondary schools in England are no more independent of raw-scores than the
raw-scores are independent of the schools’ intake values. Paterson (1997) found
similarly high correlations between raw scores and the results of regression analyses
based on pupils’ prior qualification.
The same correlation appears
Figure 1 shows that the same relationship, previously noted in the DfES value-added
figures for secondary schools in England and by Paterson (1997) in Scotland, also
appears in the DfES value-added figures for primary schools. There is a very clear
quasi-linear relationship between the KS2 raw-score for any primary school and its
eventual value-added score. All of the high value-added schools (e.g. above 101) have
relatively high raw scores (e.g. around 27 points or above). All of the low value-added
schools (e.g. below 99) have relatively low raw scores (e.g. below 29 points).
Figure 1 - Crossplot of value-added scores against Key Stage 2 results, 457 primary
schools, 2005