Monday, September 24, 2012

Partisan language, and interpreting polls

If you think that the tone of debate on Parliament Hill has become more partisan in recent years, it’s not just you. An analysis of House of Commons’ transcripts shows how one portion of the daily routine in the House has been increasingly used for partisan ends since the Conservatives came to power in 2006.

You can read the rest of the article on The Globe and Mail website here.

I also have a column in The Hill Times this morning dealing with the importance of interpreting a poll within proper context, and how interpreting it falsely can lead to false narratives. You can read my column here, but you'll need a subscription to The Hill Times (a smart investment).

In the column, I mention the recent Angus-Reid poll in British Columbia that showed a statistically insignificant increase for the B.C. Liberals, prompting headlines that the party was on the upswing. The column was written before this weekend's Ipsos-Reid poll, but the reaction to that poll is another perfect example of how polls need to be put into proper context.

I will look into the entrails of the poll in more detail later this week, but the important numbers are 32% for the B.C. Liberals and 12% for the B.C. Conservatives. That 32% was heralded as terrific news by Liberals in the province, and added to a narrative that formed over the weekend - that the B.C. Liberals are not quite dead and that the B.C. Conservatives are not a legitimate alternative.

John Van Dongen, the party's only sitting MLA (he crossed the floor from the Liberals) decided to quit the party over the weekend, justifying his departure with John Cummins' inability to make gains in the polls. Would he have felt the same way if the only numbers he had to go on were the ones from Angus-Reid and Forum, showing only a small gap between the two parties? Or was he basing that decision in part on the new Ipsos-Reid poll, that put the B.C. Liberals 20 points ahead of the Conservatives?

Trumpeting the Ipsos-Reid poll as terrific news for the B.C. Liberals is a bit of a problem, as it must assume that the polling firm is acting in a vacuum. This is the kind of poll reporting that Nate Silver criticized last night.

As you can see from the chart above, the B.C. Liberals have consistently over-performed in polls by Ipsos-Reid - on average by about six points. Both Forum and Angus-Reid have had the Liberals at much lower numbers. The good result from Ipsos-Reid is not, then, a sign that the Liberals are on a real upswing from the mid-20s of recent months. They have merely experienced a statistically insignificant increase from a polling firm that generally gives them better results.

That is not to say that Ipsos-Reid is wrong. There is every chance that Ipsos-Reid is closer to the mark and that Angus-Reid and Forum are under-scoring the B.C. Liberals. But placing Ipsos-Reid's numbers within context is absolutely essential in interpreting this poll correctly. Otherwise, the headlines accompanying the next poll from Forum or Angus-Reid have a good chance of falsely giving the impression that the B.C. Liberals are slipping once again.