The Princess Bride Problem

You keep using that word. I do not think it means what you think it means.

This is a very famous line spoken by the character Inigo Montoya in The Princess Bride. Statistics used in public debate and research often have a similar difficulty: a statistic may not mean what some people think it means.

This article will consider a few examples.

‘Most children in poverty are in working families’

This is a statistic commonly cited in response to Government ministers and spokespersons citing the latest ONS labour statistics. For instance, Mike Amesbury MP (Labour, Weaver Vale), the Shadow Minister for Employment, stated in a press release:

Many people are trapped in low paid, insecure work and 70% of children in poverty now live in working families.

In the Department for Work & Pension’s Households Below Average Income report, there are five definitions of poverty (or low income).

A household is defined as being in poverty if its net disposable household income lies below a specified threshold: 60% of the median (the middle value). This is given for both relative low income — meaning the threshold moves as average income changes — and absolute low income — the median income in 2010/11 and moves it in line with inflation. Weekly net equivalised household income is expressed both before and after housing costs.