The issue of marriage and family life looks set to be a key election battleground. In recent weeks, the Conservative Party's policy on supporting marriage in the tax system - re-stated in the family section of their Draft Manifesto published this week - has been under the spotlight. A Green Paper on family policy is due to be released by the Government next week. Recently-published IFS analysis, and two new projects funded by the Nuffield Foundation, hope to shed light on some of these issues.

The Conservative Party's wish to recognize marriage in the tax system, and many of the recommendations made by the Centre for Social Justice on family life, are justified by their proponents by the fact that in general children born to parents who are married do better on a wide range of outcomes than children born to cohabiting couples (and indeed to lone parents). But marriage itself may not be at the root of this difference, since cohabiting and married couples with children differ: for example, cohabiting parents are typically less educated, younger, and have a lower household income than married parents, and they may also differ in their relationship quality and stability. There has been remarkably little systematic work from the UK to date which investigates these important issues, and a new and substantial research project at the IFS will assess the impact that being born to non-married parents has on UK children's outcomes, trying to tease out how much of the observed differences might be genuinely attributed to the state of marriage.

The Conservative party have also said that they wish to reduce the couple penalty in tax credits, presumably by increasing the working tax credit for couples with children, and that funding for this policy would come from savings in the welfare budget. By "the couple penalty", we mean the change in entitlements - usually a fall - to benefits and tax credits that occurs when two single people (with or without children) start to cohabit. In theory, the existence of a couple penalty can give couples an incentive to live apart, rather than together, and to act fraudulently when claiming means-tested benefits or tax credits. In another new research project underway at IFS, which will produce results in a couple of months, we will provide a descriptive analysis of the "couple penalty" and how it has changed in recent years.

Finally, the IFS has recently published analysis, commissioned by Gingerbread, of the impact of three different tax and benefit policies on family incomes, work incentives and child poverty. The policies were a transferable personal allowance for married couples with children of certain ages (a policy which featured in the Conservative Party's 2001 election manifesto, and was recommended to the Conservative Party by Lord Forsyth's Tax Reform Commission, and Iain Duncan Smith's Centre for Social Justice), a higher working tax credit for couples with children, and higher child elements of the child tax credit for all families. It updates some previous work, which discusses what features of the tax and benefit system lead to couple penalties being present. The intention is that our new analysis of the couple penalty, described above, will allow a more complete comparison of these different policies.