The ONS published its 2011 data on the gender pay gap last week. The figures show the continuing gradual reduction of the gap between women’s and men’s pay. Much of the discussion has focused on the opening up of a slight pay gap between full-time twentysomething women and men. For the first time, the gap favours women. This has been coming for some time. By the middle of the last decade, the full-time gender pay gap had all but disappeared for those in their twenties and the relative performance of women and men at degree level was bound to show through sooner or later.

Perhaps more interesting, though, is the drop in the full-time pay gap for those in their thirties. Last time I looked at this, using 2006 data from this ONS study, the full-time pay gap between men and women opened up sharply for those in their thirties. This being the point at which women start to have children, it is reasonable to assume that motherhood, and the fact that the resulting childcare duties are rarely equally shared, is largely responsible for the gender pay gap. Other data in the study support this conclusion. Pay gaps are wider the more children people have and there is no gap between single man and single women of whatever age. (See previous post.) Women with children tend to commute for shorter distances, which also limits their options.

Since the 2006 study, though, the thirtysomething full-time pay gap has reduced to the point where it has almost disappeared. The ONS only started publishing these figures in 2009 but an educated guess, based on the above graph, would be that the thirties pay gap was probably around 7 percent in 2006. Since then, it has dropped to this year’s 1.1 percent.

Gender pay difference for median hourly earnings, excluding overtime Percentage full-time pay difference (men/women) by age band

Why should this be? Perhaps childcare is better, or maybe employers are adopting more flexible policies. Then again, it could be that women are delaying having children so the motherhood pay gap opens up later.

Could some of it be due to a shift in social attitudes? Many of the women now in the thirties cohort would have been in their twenties in 2006; part of that group used to earning as much, if not more, than their partners. Maybe they are demanding more of their employers and spouses, refusing to down-shift and take the lower paid jobs closer to home and the school run.

Of course, the overall pay gap is still there, showing that a lot of thirtysomething women are still opting to take part-time work, which, as a rule, pays lower hourly rates. But the fall in the disparity between full-time male and female earnings among those in their 30s is pronounced.

It’s too early to say whether this indicates a change in social attitudes or, indeed, whether the trend will continue. And it’s waaaay to early to make predictions like this. The reduction in employment levels and a prolonged pay freeze in the public sector, which employs a disproportionate number of women, could throw the trend into reverse or, at least, stop it in its tracks.

All the same, it is an interesting development. I’d be fascinated to hear from anyone who has any more information on this or, for that matter, any theories as to why the thirtysomething pay gap seems to be going the way the twentysomething one did.

Answers, suggestions, data and theories (crackpot of otherwise) in the usual place please.