Comparing distributions - err, no

This chart came my way via Twitter - it "shows" the progress from Key Stage 2 to Key Stage 3 for the learners from a specific primary school.

I say "shows" as it gave me a headache trying to decipher what the chart is actually showing.

Issues:
  • X-axis as KS2 levels - that's OK
  • Y-axis as "number of pupils at KS3 level" makes the chart difficult to read, as the numbers on this axis don't directly link to the x-axis
  • KS3 levels as series (and different colours) makes it doubly difficult to see what's happening.

As a parent I want to know - how much progress do the learners from this school make between KS2 and KS3 - an interpretation that is almost impossible to deduce from this chart.

Some Excel-fu and a bubble chart later:


I can see:
  • 1 level of progress (2 to 3, 3 to 4 and 5 to 6) is the most common
  • Some learners make 2 or 3 levels of progress
  • 3 learners incoming with level 4 left KS3 with a level 3 (so went down)
  • 31 learners made no progress from KS2 to KS3
Call to action
When you make a chart run it past some parents - if they can't "see" what the chart is showing, then you may need to find an alternative visualisation.



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