Voting intention polls – the fools’ gold of predicting elections. Leader ratings do it better

Voting intention polls – the fools’ gold of predicting elections. Leader ratings do it better

A week before GE17 and TMay’s best PM dominance is crumbling

4 days before GE17: few pay attention to Ipsos’s satisfaction numbers

PB regulars will know that every so often I have a little rant about how leader ratings are a far better guide to election outcomes than voting intention polls.

At the top I highlight Tweets by myself and TSE posted in the final week before the last election when almost all the polls were still showing the Tories with a pretty good lead and heading for a comfortable majority while the leader ratings were signalling that the Tories might be in trouble. In its final poll YouGov had Corbyn level-pegging with May for best PM.

It wasn’t as though this was a new phenomena. Two years earlier at the 2015 General Election the same thing happened. The voting polls had it neck and neck yet the leader ratings had Cameron maintaining a clear margin over Ed Miliband.

Four years earlier in 2011 the big news was the collapse of Labour in the Scottish Parliament elections and a majority for the SNP. Less that 10 weeks beforehand the voting polls were suggesting a LAB majority. The eventual outcome was all highly predictable, as I noted here at the time, because Alex Salmond was getting so much better ratings than his Labour opponent.

I could go back with example after example where the voting intention polls really were not a good guide to the general election. The most striking one was GE1992 when John Major had double digit lead over Neil Kinnock in the ratings but was level pegging in the voting polls. Major, of course, had his surprise victory and went on to win an overall majority.

    The reason I would suggest is that opinion polls are far better when they are doing just that – asking people their opinions. With voting intention questions respondees are expected to predict whether they will take part in an event which may be five years hence and also to indicate how they might make a choice. That I would suggest is a very difficult thing to get right.

I should say that the voting polls do often come good but if they are showing a different picture from the leader ratings go with the latter.

At the moment with the voting polls pretty much tied I would say the worry for Labour is that Corbyn is still quite some way down on the best prime minister ratings.

Mike Smithson

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