Following our recent article on what the Value-Added performance measure is, (and why it’s important), we wanted to follow up with an explanation of how to calculate it.
Put simply, by comparing an individual student’s Average Points Score (APS) at Key Stage 4, we can use both the prior attainment and actual results of previous students to predict what grade our current student is most likely to get. If the student scores above that prediction, that is seen as a ‘Value Add’ (or value lost, potentially) and this is how L3VA is measured.
Calculating the Average Point Scores for the Qualifications at KS4
Our first step in calculating Level-3 Value Added Scores is therefore to work out the Average Point Score for each student’s results at Key Stage 4.
For GCSEs, points are allocated in line with the new grades, hence a grade of 6 is allocated 6 points. For any students taking non-GCSE qualifications at KS4, the Department for Education publishes a list each year allocating points for each of the grades possible in the range 9 – 1.
The Average Point Score (APS) for any individual student is therefore simply the mathematical average of their results divided by the number of qualifications they took. For example, a student who achieved two GCSE passes at grade 5, two GCSEs passes at grade 6, one GCSE pass at grade 8 and a BTEC L2 Merit (worth 5.5 points) would generate an APS of 5.92. (Calculated as: 5+5+6+6+8+5.5 = 35.6 /6 qualifications =5.92 average)
Calculating the National Average Grades
The next step is to calculate the national average grade of every level 3 qualification which falls under the scope of the L3VA measures.
This is done by plotting the results of previous students to compare their APS at KS4 with their actual Level 3 results. Results are banded equally by percentile based in order to give an average attainment result for students of an equivalent prior achievement.
For example, the average APS at KS4 of each student who took A Level Physics and their actual A level grade are plotted on a chart. We can then use this chart as a predictive tool for our current students taking A Level Physics: if an individual had an APS that falls in the top percentile band, it is likely that their A level result will fall in line with the results the top percentile band achieved too. Equally, if a student had a lower APS, it is also likely that their result will fall in line with the results of their predecessors in that band too.
Calculating student value added scores for individual qualifications
Where our predictions based on this banding turn out to be inaccurate – a student does better or worse than we predicted – this is the measure of Value-Added. So, if we predicted that one of our A Level Physics students was likely to achieve a grade C, based on our APS/results chart, but that student actually achieved a grade A, we would calculate that as a Value-Added score of +2. It also works the other way around: if a student was predicted to achieve a grade B but actually only achieved a grade C, that would show as a Value-Added score of -1. These are illustrated by the chart above.
By aggregating all the results of students on the same physics course, we can determine the overall Value-Added score for the course.
In the same way, all the results for all the A Level and Applied General qualifications may be aggregated to calculate an overall value-added score for the college and this will be displayed as Headline Measure on the Schools and Colleges Comparison Site – see: https://www.compare-school-performance.service.gov.uk/
Further Useful Information
Our chart is reproduced from Annex B of the 16-19 Accountability Measures Technical Guide: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/819734/16-18_Accountability_Measures_Technical_Guide_July_2019.pdf
The Department for Education generates charts like the one above for all Academic (e.g. A levels) and Applied General Qualifications. The results for the latest sets of data for the academic year 2018-2019 are about to be published (at the end of January 2020) and appear in a very clever spreadsheet called the “Level 3 Value Added Ready Reckoner: 2019” – see the link: https://www.gov.uk/government/publications/16-to-18-level-3-value-added-ready-reckoner
Our next article will look at the Completion and Attainment measure and how that relates to students studying Tech Levels.