The UK’s new majority Conservative government seems to have a problem with averages.
Iain Duncan Smith – IDS to many – has announced he is to do away with one measure of the numbers of UK children living in poverty. Known as relative income poverty, or just relative poverty, it classifies households as poor if their income – taking into account family size – is less than three-fifths (60%) of median income. The median is a type of average which marks the “middle” of a distribution – half the numbers are below the median, half are above.
IDS doesn’t like this. He highlights the weakness of the measure which means levels of relative poverty can drop when incomes generally fall – as they did after the 2008 financial crash. However, bodies such as the Joseph Rowntree Foundation (JRF) and the Royal Statistical Society (in 2013) have warned against abandoning an income measure altogether.
Meanwhile, Secretary of State for Education, Nicky Morgan, seems more positive about her averages – using them to define when a school is to be deemed ‘coasting’.
Her department’s press release seeks to explain (my emboldening):
- For secondary schools, a school will be ‘coasting’ if in 2014 and 2015 fewer than 60% of children achieve 5 A* to C including English and mathematics and they are below the median level of expected progress and in 2016 they fall below a level set against the new progress 8 measure. This level will be set after 2016 results are available to ensure it is set at a suitable level. A school will have to be below those levels in all 3 years to be defined as ‘coasting’. By 2018 the definition of ‘coasting’ will be based entirely on Progress 8 and will not have an attainment element.
- At primary level the definition will apply to those schools who for the first 2 years have seen fewer than 85% of children achieving level 4, the secondary-ready standard, in reading, writing and maths, and which have also seen below-average proportions of pupils making expected progress between age 7 and age 11, followed by a year below a ‘coasting’ level set against the new accountability regime which will see children being expected to achieve a new higher expected standard and schools being measured against a new measure of progress.
It’s good that our political leaders want to use statistics and statistical principles to guide their policy development and monitoring. But they need to be sure that their choices are statistically sound.
After all, while all politicians can’t have above-average statistical skills they can at least all be adequate or better.
- If you want to freshen up your basic stats skills – whether to lobby politicians or for a wider campaign – my workshops can help. Get in touch to discuss your needs.