Should The Observer have consulted a bookmaker?

There was a reasonably interesting piece in The Observer yesterday, speculating on whether Cameron could get a majority in 2015. Here are Ladbrokes’ latest odds:

The Tories are 3/1, indicating a 25% possibility. For a lot of people reading this blog, I suspect the starting point for answering the question,”Will Cameron win a majority” would be to look at the betting markets and instantly answer that there is about a one in four chance of that happening. No need to ask lots of talking heads, end of story.

I certainly don’t think that the betting markets are the only worthwhile way of answering such questions. A lot of the time, there isn’t much money floating around on political markets and they could be reasonably easily manipulated by someone with a few quid and a strong opinion (not that I really think there is much of that going on). But, in the case of the big topline events like this, the markets are mostly quite liquid and efficient.

Still, if I were writing a piece on, say, whether oil prices would hit a certain mark a year from now, I think I might ask an oil trader for their opinion. Someone whose job it was to estimate the likely probabilities and who most likely would not be in that job if they didn’t have a fair record of getting it right.

In The Observer’s defence, they did ask some quite interesting people whose views are worth hearing on the matter. They asked a pollster, some respected party activists and have even got a bit of political science in there with Tony Travers and Stephen Fisher. (Some of that only appears in the print edition). I still think they should have asked a bookie as well, or at the very least have made a reference to the odds.

A couple of other points about the article:

• They felt the need to preface the result of Lord Ashcroft’s polling as coming from the “billionaire Tory peer”, as if that were relevant. Experienced poll watchers will know that Ashcroft’s polling is some of the best around and it’s clear that he does his very best to produce impartial scientific numbers.
• For some reason, they decided to pick Birmingham Northfield as a constituency worth talking about, describing it as a “marginal seat” and that “the Conservatives hope to take it next year.” I’m sure they probably do hope to take it, but this is a long way down their target list and Cameron will have won a very tidy majority long before they get to winning seats like this. Ladbrokes make Labour 1/33 to hold Northfield.

UPDATE: Ladbrokes have now cut the price of a Conservative majority to 11/4 from 3/1. In percentage terms, those odds represent an increase in the probability from 25% to 26.7%. We took quite a lot of money on Monday morning, probably prompted by the latest Populus poll showing the Tories ahead of Labour 35-34%.