Wednesday, April 27, 2011

Change in Vote Share Adjustment

It is now apparent that there is a large voter commitment gap between the Conservatives and the Liberals (not surprising given the way the Liberal campaign is going). See the latest EKOS and Angus Reid polls for evidence. Starting with the next projection, I will make the following methodological change:

Current Vote Share Adjustment: I reduce the vote shares of the Greens and Bloc, and distribute the deductions among the three main parties. Then I reduce the vote share of the NDP, and distribute the deduction among the Tories and Grits.

New Vote Share Adjustment: The first step with the Greens and Bloc remains the same. However, in the second step, I will give the NDP deduction entirely to the Conservatives.

This change effectively shifts half a point from the Liberals to the Conservatives. It doesn't affect the NDP's estimated share (which is still penalized about 1% relative to the raw polling average), but will (very modestly) help the NDP in races against the Liberals and hurt it in races against the Conservatives.

5 comments:

Bryan Breguet said...

I was thinking about something regarding voters commitment. I'm sure we can find a poll from Ekos or AR that is 3 weeks old where 75-80% of Bloc supporters were sure to vote for the Bloc. Yet, 3 weeks later, the Bloc has lost like 35% if its support in Quebec (dropping from 35-38 to 25-28)... Something is not consistent there, don't you think? Especially since we still have around 80% of commitment for the remaining voters.

Election Watcher said...

Yeah, all this is pretty much guesswork. Many people probably think they're committed until they change their mind. I originally gave bumps to both the Grits and Tories because the Liberals got it in 2004 and 2006, while the Conservatives got it last time. But the dynamics this time are really really bad for the Liberals.

Jeremy said...
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Jeremy said...

Remember how the 2008 estimates undervalued the Tory vote, because they were surging?

This time it's the NDP that's surging, and your model is going to miss that in just the same way.

NDP commitment will be softer because it's new... but people LIKE to vote for an underdog that's suddenly a winner. Penalizing the NDP at this point seems just wrong. Where before NDP voters might have walked into the poll and said "Hm, maybe I should vote for the Grit or the Bloc again to block the

Election Watcher said...

Jeremy: Again, the Tories were surging in the last couple of days, which is very different from what we have now. It could be that the NDP surge will continue. But it could also be that the NDP is peaking too early, and will lose a few percent at the end. We just don't know.

What we do know is that the NDP electorate is overwhelming young, and that young voters turn out less. I think that's what my adjustment captures, and I believe that after my adjustment, there is roughly equal risk on both sides.