What is it with YouGov and female voters?

It’s a well-established pattern that during this Parliament internet pollster YouGov consistently gives the Liberal Democrats lower levels of support than other pollsters (as, for example, I previously blogged about on this site).

Looking at the details of polls published so far this year, this pattern remains but there is also an interesting detail when it comes to male versus female voters.

YouGov, MORI and ComRes are the three of the main polling companies who also provide a gender breakdown of party levels of support using the same methodology as for their headline voting question.

Comparing the results they find for each party for men and women, we find the following average gender gaps in each party’s support:

YouGov (21 polls): Conservative support 3.6% higher amongst women than men*
MORI (13 polls): Conservative support 1.7% lower amongst women than men
ComRes (12 polls): Conservative support 1.3% lower amongst women than men

In other words, whilst YouGov consistently finds the Conservative party more popular amongst women than men, the other two consistently find the opposite. There is a similar difference amongst the pollsters when it comes to Labour support, though this time the gender pattern is reversed:

YouGov: Labour support 1.6% lower amongst women
MORI: Labour support 1.9% higher amongst women
ComRes:  Labour support 0.8% higher amongst women

There is also a difference for Liberal Democrat support, though less striking as all three pollsters consistently give the party more support amongst women then men (YouGov by 0.3%, MORI by 1.5% and ComRes by 2.1%).

It would appear that there is something very different between YouGov and other pollsters when it comes to counting Conservative support amongst women. Indeed, YouGov’s average Conservative ratings amongst men are much the same as MORI and ComRes (43.0% compared with 42.2% and 43.4%) but amongst women there is a big difference (46.6% compared with 40.5% and 42.1%).

It’s not obvious to me how the differences in methodology between the polling companies would explain this difference, but as the difference has been sustained over a large number of polls all through the year, there does appear to be something real at work.

* This figure is still 3.1% even if you exclude the last two YouGov polls which had very high gender gap figures of 7% and 9%.