I like graphs and charts. It's part of my job to use them to communicate data effectively. I try to do so clearly and fairly.. because there's usually nothing to be gained from hiding from the truth.
Eoin Clarke has done a chart here to show why Independent schools are much worse than comprehensive schools. As we can see, their GSCE results are much worse.
Oh.. but wait.. they're not. They're very slightly worse.. but he's used a deeply selective and misleading scale to make a difference of 0.4% look huge.
I did a chart using the same source data. But I added a second set, which shows the comparable GCSE results for the schools, but for pupils who got 5+ GCSE passes including maths and English. I'm not saying that this is a more telling indicator of quality.. that's for the reader to decide.
I've also used a selective and misleading scale.
Aren't comprehensive schools RUBBISH!
Here's another chart.. with a proper scale.. that shows the relative performance differences according to whether one thinks that Eoin has chosen the best measure, or whether ones thinks that we should take into account whether or not pupils can read, write and do sums.