Abolishing child poverty by 2020 has been one of this Government's defining policy goals for almost a decade. Last week ministers tried to make it a little easier, suggesting that it would be enough to cut the proportion of children in poverty on the most familiar definition to 10% rather than the 5% they have so far aspired to.

Claiming to have abolished child poverty with 1 in 10 children still below the poverty line is not as daft as it sounds. Numerous studies have shown that many households with very low incomes enjoy high living standards, suggesting their incomes are mis-measured or that they are poor only temporarily. Historically, child poverty in Britain has never fallen as low as 10% since the consistent series began in 1961, so hitting the new target would hardly be a cinch.

In addition to loosening the relative income target, the Government has suggested looking at two other measures too. It will aim to remove all children from material deprivation and persistent poverty. These are sensible complementary measures, although the precise definitions have yet to be set. It is noteworthy that the Government still wants to equate poverty firmly with low household income, rather than a wider range of circumstances. Although this may fit with most people's understanding of poverty, it risks skewing the policy response towards redistribution through cash payments, rather than - for example - better public services to improve children's lives.

Cynics may suggest that the focus on child poverty in 2020 is to deflect attention from the Government's existing target to halve child poverty from its 1998 level by 2010. Despite considerable extra spending on families with children in the past two Budgets, we estimated last summer that the Government would miss this target, just as it missed its earlier target one for 2004.

New data on household incomes, and the dramatic change in the economic climate over the past year, have led us to update that forecast and our estimates of how much it would cost to meet the 2010 and 2020 targets. This work, funded by the Joseph Rowntree Foundation, was published and presented at an IFS briefing on 18th February 2009.