Research publication: First births and the Great Recession in the UK

The research publication Differential responses in first birth behaviour to economic recession in the United Kingdom was finally online published today in Journal of Biosocial Science, and can be found here (£).

I'm not going to go through the findings of the paper in detail in this post, but more concentrating on some things that didn't make it into the paper- namely the sort of claims that can be made from natural experiment type of events that the Great Recession represents.

The Great Recession was really fortunate in terms of social science study design (less so in terms of other consequences) as it makes it relatively easy to make causal inferences. There are two key features that make this design nice:

1. The recession was relatively unexpected. Although there had been some instability in financial markets in the upcoming months in terms of US sub-prime and things like BNP, the actual crash itself came as something of a surprise (most recessions are, relatively few populations have repeated warnings about potential economic slowdowns in the medium and long term but still decide to plough ahead anyway). As such, we don't get anticipatory effects that we get where such a 'recession discontinuity' (here all week) is predicted since policy reforms tend to be announced in advance- although there are notable exceptions.
2. The recession, as a cross-national macro-economic event, was exogenous with respect to the individuals it affected. 

As such, the recession is a reasonably nice natural experiment. There are some limitation in terms of what we can claim that said: since this is not a true discontinuity (there is a reason the pun didn't make it into the title) but an economic shock, the causal effect in terms of fertility behaviour should be limited to a relatively short period surrounding the crash before we start to get into problems of what is the effect of the recession and what are the effects of the policy responses to the recession. We didn't end up doing this in the paper due to sample size and because we wanted to make inferences about older women to capture cohort effect: others have although they don't examine the heterogeneous effects of the recession that we do. The paper is therefore capturing effects on fertility beyond those of the natural experiment, although it was probably worth doing so to get an idea of the various effects on different social groups.