As a follow-up to my previous post about STV, and in response to queries from a couple of people, I thought the following might be of interest to some readers of the Blog.
As mentioned in my previous post, the 2011 Welsh Election Study not only asked respondents immediately after the election how they had voted, but also fielded a question which asked:
“Please indicate how you would have voted in the National Assembly for Wales election if you had been asked to rank the parties in your order of preference. Put 1 for your most preferred party, then 2 for your second best party, 3 for your third choice etc. You may rank as many or as few choices as you wish.”
Most interesting, I think, about answers to this question is not who wins the first preferences (first preferences won by the parties were very close to the proportion of actual votes that they won in the Assembly election) but who is then chosen as the second preference.
Below I list the second preference choices by party: i.e. what those who said they would favour a party with their first preference then said they would do with their second preference. (The percentages given don’t sum up to 100: some people only indicated a first preference, while a handful gave their second preference to parties too minor to be listed here):
Of those indicating that the Conservatives would have received their first preference vote, second preferences were allocated as follows:
23.5% Liberal Democrats
For Labour first preference voters, second preferences were:
10.3% Liberal Democrats
For Liberal Democrat first preference supporters, second preferences were:
For Plaid Cymru supporters, second preferences were allocated:
21.6% Liberal Democrats
For the (small number of) Greens, the proportions of second preferences were:
17.9% Liberal Democrats
Finally, for UKIP supporters, the profile of second preferences was:
5.4% Liberal Democrats
5.4% Plaid Cymru
So what can we make of these numbers? Overall, I think they reinforce what I said in my previous post. To do well in a preferential voting system, a party first of all needs to win lots of first preferences. But it also need to be fairly attractive to supporters of other parties to pick up vote transfers. The data suggests that while the Conservatives would do reasonably under STV in terms of first preferences, they would struggle to win many vote transfers. (I’ve only shown second preferences here, but things don’t get any better for them when you look at third or even fourth preferences). On second preferences, the Tories are not even the plurality choice among the diminished ranks of their Liberal Democrat coalition allies. They are only the most popular choice among (the then fairly small number of) UKIP supporters.
Labour would seem to do well out of STV. Not only does it gather a large number of first preferences; it is also the most popular second preference choice for Liberal Democrats and Plaid Cymru supporters, as well as among small number of Greens.
Plaid would also seem to do quite well out of STV: certainly, they are much the most popular second preference choice among the large pool of Labour supporters. However, this finding also re-emphasises a point I have made previously: there were lots of voters in 2011 who felt quite sympathetic to both Labour and Plaid, but Plaid was very poor at getting many of them to make it their first choice.