Labor swims ahead in the pooled poll

Over recent weeks, several betting houses have been pooling several polls into one, in an attempt to reduce their standard errors. Now Simon Jackman (who wrote a paper after the 2004 election called “pooling the polls”) has crunched the data for 2007, pooling all the Galaxy, Nielsen, Morgan and Newspoll polls into a single estimate. This is handy if you think that some pollsters have “house biases”, causing them to systematically favour one side or the other.*

Simon’s bottom line: the pooled poll shows a very strong likelihood of a Labor victory (much stronger than the implied probability from the betting markets). His mean estimate of the ALP 2pp voteshare is 54%, with a 95% confidence interval running from 52-56%.

OK, now here’s a challenge for the betting agencies: why don’t one of you run a betting market on the two-party preferred vote? That would give us a direct head-to-head way of comparing polls and markets.

* Assuming the polls “house biases” offset each other, that is.