6 Feb 2015
Value added scores tell us how well our students have done, based on their prior attainment. The best data to use for this is currently Best 8 VA, as this will be the basis for the new Progress 8 measure. However, P8 is based on scaled SATs scores, which we don't currently have available. The reason for this innovation is that there is much argument about whether it is (or should be) easier to add value to high attaining students or low attaining ones. Scaling removes this discussion.
So, the schoolzone number crunchers have come up with a way of looking at your existing data to see how well you're likely to do, based existing data.
A Best 8 VA score of 1000 is average - a table of five schools chosen almost at random (except that the one at the top is my school, another is a local grammar and one is a recently reinvigorated academy). You can see, even among these few schools, that it's difficult to see which has done best in comparison to the KS2 performance.
Best 8 VA
A good way to see how much value schools have added, removing (or at least reducing) the impact of KS2 data is to plot Best 8 VA against KS2 average point score, as we've done below.
The red line is a best fit (or Trendline if using Excel). Schools which are close to the line have added a typical amount of value. Those furthest above it (perpendicularly) have added most value.
You can see from the KS2 points that School B is a grammar - it has high performing intake, but it's underperformed compared to the average.
As has School E, which has a low performing intake, but has performed very poorly in terms of adding value, whereas School C, with a similar intake had performed incredibly well.
Progress 8 expects schools to be just above the red line in order to be above floor standard. Even being on it is not good enough.
If you're running this exercise for yourself, use more schools' data in order to give a more accurate line of best fit - our example above is for illustration only.
PS - grammar schools have until now had an artificially reduced KS2 points score, because reported SAT scores do not currently reach as high as their students' ability. In new SATs, they will, so you'd expect School B to be further to the right, and therefore even further below the red line.
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