“Official figures show that since 2010, child poverty has increased by half a million”

That was the claim from Jeremy Corbyn at Prime Minister’s Questions.

But it only tells half the story.

Where’s the figure from?

One likely source is this report by the Joseph Rowntree Foundation.

The paper, published in December 2018, says “Child poverty has been rising since 2011-12. In the UK 4.1 million children now live in poverty, a rise of 500,000 in the last five years”.

The report also notes that “this is much faster than we would expect based on population growth: the total number of children has risen by 3 per cent, while the number of children in poverty has risen by 15 per cent.”

The Foundation study can only be based on the 2018 edition of the government’s “Households below average income” figures.

These stats show that in 2011-12, there were 3.6 million children living in “relative low income households after housing costs”. Five years later, in 2016-17 (which would have been the latest data available at the time of the report), that figure was 4.1 million.

Mr Corbyn cited the “4.1 million” number in November 2018 in a letter to the Prime Minister. He also repeated the “half a million” increase claim in December 2018.

You can also get the same 500,000 growth by comparing figures from 2010-11 to the latest government stats for relative poverty out in March 2019. It’s possible this is what he had in mind today.

Relative versus absolute poverty

Mr Corbyn talks about “child poverty”, as does the Foundation report.

But he doesn’t mention one important caveat: the 500,000 figure refers to “relative poverty” not “absolute poverty”. So what’s the difference?

In simple terms: imagine you lined up everyone in the UK in order of highest to lowest income. The household in the very middle of that line is on the median average income. A household earning less than 60 per cent of that person’s income is officially below the “low-income threshold”.

A household in relative poverty (or as it’s referred to in the official statistics, “relative low income”) is below the low-income threshold for that year. The relative poverty measure can tell us about the current state of inequality in the UK.

By contrast, a household in absolute poverty is below the low-income threshold for the year 2010-11, regardless of the year we’re studying. The point of the absolute poverty measure is it allows us to make comparisons over time against a stable benchmark.

How has absolute poverty changed?

If Mr Corbyn’s referring to the Rowntree Foundation report, the 500,000 figure comes from comparing the number of children in relative poverty in 2011-12 to the number in 2016-17.

But if so, Mr Corbyn has not mentioned that in the same time frame, the number of children in absolute poverty fell by 300,000. It was 3.8 million in 2011-12, but dropped to 3.5 million in 2016-17.

In March, the government released new official statistics in the same dataset. They show that 3.7 million children were in absolute poverty in 2017-18. That is a rise of 200,000 compared to 2016-17, but still 100,000 lower than it was in 2011-12.

If we look more widely — from 2010-11 to 2017-18 — the number of children living in absolute poverty has increased by 100,000 over that time. Over the same period, the total number of children in the UK rose by 600,000. So while the number of children in absolute poverty went up, the percentage of children in absolute poverty went down.

FactCheck verdict

Jeremy Corbyn claimed that “since 2010, child poverty has increased by half a million”.

We assume he’s referring to a 2018 report from the Joseph Rowntree Foundation, which compared government figures from 2011-12 and 2016-17. Although he could be referring to more recent figures.

Either way, Mr Corbyn didn’t mention one key caveat: he’s referring to a rise in relative poverty, not absolute poverty.

If we’re looking at the 2011-12 to 2016-17 period, which is consistent with the claims Mr Corbyn has made elsewhere, the number of children in absolute poverty actually fell by 100,000 in that time.

If we look more widely at the period 2010-11 to 2017-18, the number of children in absolute poverty (which is the measure better designed for making comparisons over time) rose by 100,000. Over the same period, the total number of children in the UK rose by 600,000.

Update, 3 April

We’ve updated this article to make clear that Mr Corbyn could have had an alternative timeframe in mind to the one set out in the Joseph Rowntree report.