Marital status, child outcomes, and why good evidence is crucial in policymaking

25 October 2013

The Institute for Fiscal Studies has published new findings from a project to examine the link between parents’ marital status and relationship stability and child outcomes.

It shows that married parents are, on average, less likely to separate while their child is young than cohabiting parents. It also shows that children born to married parents have slightly higher cognitive and socio-emotional development, on average, than children born to cohabiting couples; they are also less likely to engage in risky and antisocial behaviours, such as underage smoking, drinking and cannabis use.

In light of this, the researchers pose the question: ‘Does this evidence prove that marriage causes improvements in relationship stability and child development?’

They conclude that it doesn’t, because once all other differences apart from marital status are accounted for, the link between marital status and relationship stability or child development is substantially reduced or even eliminated. For example, there is little difference if you compare cohabitating and married parents who have very similar home environments, levels of education and ethnic background.

This suggests that much of the raw relationship is due to the fact that different types of people choose to get married, rather than that marriage has a large causal effect on relationship stability or child outcomes.

Why this distinction is crucial in policymaking

The IFS reflect on these findings to illustrate a wider point about evidence and policy-making, arguing that understanding whether and to what extent factors are causally related or simply correlated is crucial. Policy decisions should ideally be based on evidence of a causal relationship. Where that is not possible, it is important to be clear about exactly what we do, and don’t, know.

The work published today on the link between parents’ marital status and relationship stability and children’s outcomes is a good example of this. There is a strong correlation between parents being married and children who are more successful academically and in other ways. But there is not good evidence of a causal link – though we can’t say for sure that such a link does not exist.

Researchers must be careful not to interpret or present statistically significant associations as evidence of causation. In turn, policymakers must be cautious about using such associations as a basis for policymaking.