The average income of households with children will drop by 4.2% - or £1,250 - a year between 2010/11 and 2015/16 as a result of the coalition's tax and benefit changes aimed at reducing the deficit, a charity has calculated.
However, the average household income will decline by 0.9%, or £215, a year, says the Family and Parenting Institute (FPI), based on research carried out by the Institute for Fiscal Studies (IFS).
The FPI suggests much of the fall in income during the five-year period will be due to tax and benefit changes, as well as other reasons such as falling incomes.
"This research confirms that families with children are shouldering a disproportionate burden," said the FPI's Katherine Rake.
"This disparity is largely driven by a package of benefit reforms which have affected families with children.
"As a result of the changes being introduced between January 2011 and April 2014 families are set to lose more than pensioner households and working-age households without children," she added.
Changes already implemented by the government include VAT at 20%, reductions in tax credits, cuts in housing benefit, a freeze on child benefits, and the use of the consumer prices index (CPI) to uprate benefits each year.
Other forthcoming changes include more changes to the child tax credit and child benefit systems, reductions in council tax benefit, and "medical reassessment" of claimants of disability living allowance.
But the government hopes its new flagship benefit - the Universal Credit, which is being phased in from October 2013 - will protect the incomes of poorer families.
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