Did working families' tax credit work? : The impact of in-work support on labour supply in Great Britain

In-work benefits are promoted as a way to make low-income families better off without introducing adverse work incentives. In 1999, the structure of in-work benefits in the UK changed, and their generosity almost doubled, through the introduction of Working Families' Tax Credit (WFTC). With micro-data from before and after its introduction, a structural model of tabour supply and programme participation estimates that, by 2002, WFTC had increased tabour supply of lone mothers by around 5.1 percentage points, slightly reduced tabour supply of mothers in couples by 0.6 percentage points, and increased the tabour supply of fathers in couples by 0.8 percentage points, compared with the programme that preceded it. Other tax and benefit reforms contemporaneous with WFTC acted to reduce the tabour supply of parents, though. Without any form of in-work benefit in the UK, tabour force participation by lone mothers would be around 45 percent, rather than the 55 per cent we now observe. Participating in family credit, the UK's in-work programme before October 1999, conferred a utility loss as well as a utility gain from the extra income, but this utility cost of participation was lower in the final year of WFTC than under previous programmes for lone mothers, and no different for individuals in couples: this in itself induced more lone mothers to work. (c) 2006 Elsevier B.V. All rights reserved.