The Times’s report of this month’s Populus poll highlighted what appeared to be a striking 7 point difference in the Conservative lead between how men would vote and how women would vote, a gap that grew to 12 points when Populus asked how people would vote with Brown as leader. There various bits of commentary on how David Cameron is winning the women’s vote. But is he?

I warned at the time that the big twelve point difference on the hypothetical question with Brown as leader might well be based on very small sample sizes - indeed it was. In fact, if you look at the gender breaks in Populus’s polls there is no obvious pattern, it bounces up and down from month to month. Back in April the Conservative lead amognst women was also 6 points higher than amongst men, but come July the Tory lead was 8 points higher amongst men.

ICM’s gender splits don’t show a steady pattern either - in their October poll male and female voting intention was almost identical, but in their two previous polls the Conservative lead was far, far larger amongst men than women. In their last poll for the Sunday Telegraph the Conservatives had a 15 point lead amongst men and a 2 point lead amongst women. In their September poll for the Guardian though, the Conservative lead was 10 points higher amongst women.

Therefore it looks as though the apparantly gender gap in the polls wasn’t significant at all, it’s just the result of the small sample sizes you get on crossbreaks throwing up erratic figures. The exception, however, is YouGov. YouGov have larger sample sizes to start with, and don’t filter or weight by likelihood to vote, leaving them with a larger sample and - in theory at least - less volatile cross breaks. Looking at the Conservative lead amongst men and amongst women on YouGov’s polls since the last election there is a noticeable pattern.

On YouGov’s crossbreaks the Conservatives have recorded a higher lead amongst women voters than amongst men in all but one poll since September 2005 (the exception had identical leads amongst men and women). On average the Conservative lead amongst women has been six points larger than amongst men. In comparison, prior to September 2005 YouGov recorded leads amongst women that were almost identical to those amongst men (if anything, the Conservatives did marginally better amongst men). It does tie up exactly with David Cameron’s emergence as the frontrunner in the Conservative leadership campaign, but certainly judging by YouGov’s figures the Tories have opened up an advantage amongst women since last Autumn.

The bottom line, therefore, is that the gender gap in one single Populus poll probably doesn’t signify much at all - but looking at the longer term picture women voters do seem to have swung more heavily to the Conservatives than male voters have.

Posted by Anthony Wells in ICM, Populus, Voting Intention, YouGov