Monday, October 19, 2015

2015 Federal Election, Final Projection: LIBERAL MINORITY

Canadian Election Watch's final projection for the 2015 federal election is as follows:

LIB - 142 (37.3%)
CON - 119 (32.4%)
NDP - 66 (20.1%)
BQ - 10 (4.9%)
GRN - 1 (4.3%)

In order to take into account the movement observed in the past few days toward the Liberals, conservative modifications were made to some polls taken earlier in the week based on the evolution of the Nanos and EKOS tracking polls. Moreover, the turnout adjustment used throughout the campaign was reduced by around one fifth outside of Québec in order to take into account movement from the CPC to the LPC among seniors. Finally, a riding-by-riding examination of the projection resulted in some seats being moved (mostly in Québec); the net effect of this was no more than 2 seats for any party.

(Update: I changed some probabilities below since a larger than usual number of ridings are tight.)

This projection implies a Liberal seat plurality short of a majority with probability around 70-75% 65%. The probability of a Conservative seat plurality is around 20-25% 25%. Either of these scenarios would likely result in a Liberal minority government. There is a roughly 5% 10% chance of a Liberal majority government. The probability of a Conservative majority and of an NDP seat plurality are negligible. (Please note that these probabilities are not derived from simulations, as would be ideal. They are instead estimated using the method outlined here.)

If you believe that polls accurately sample the electorate, you should instead refer to the projection below, which does not include a turnout adjustment:

LIB - 150 (38.3%)
CON - 111 (30.9%)
NDP - 65 (20.6%)
BQ - 11 (4.9%)
GRN - 1 (4.6%)

Such numbers imply a Liberal seat plurality short of a majority with probability around 75% 65-70%. A Conservative seat plurality and a Liberal majority have a 10-15% roughly 15% and 15-20% chance of occurring, respectively.

Therefore, depending on whether one believes in the turnout adjustment, the probability of a Liberal win is around either 75-80% or 85-90% 75% or 85%. Thus, although the Liberals are clear favourites, there is a significant chance of a slim Conservative plurality. Similarly, a Liberal majority cannot be ruled out.

The main (i.e. adjusted) projection by region is as follows:

Atlantic Canada
LIB - 26 (53.5%)
CON - 3 (21.1%)
NDP - 3 (20.2%)
GRN - 0 (4.2%)

NDP - 31 (26.3%)
LIB - 26 (30.1%)
CON - 11 (20.5%)
BQ - 10 (19.4%)
GRN - 0 (2.6%)

LIB - 71 (44.3%)
CON - 36 (34.3%)
NDP - 14 (16.7%)
GRN - 0 (3.7%)

CON - 17 (41.7%)
LIB - 5 (32.6%)
NDP - 6 (20.7%)
GRN - 0 (4.1%)

CON - 32 (56.3%)
LIB - 1 (24.4%)
NDP - 1 (15.0%)
GRN - 0 (3.3%)

British Columbia
CON - 20 (32.1%)
NDP - 11 (25.1%)
LIB - 10 (32.8%)
GRN - 1 (8.9%)

LIB - 3

As you can see, the Liberals are projected to win the popular vote in Québec, but due to the concentration of their vote, they are projected to win fewer seats than the NDP. It should be noted, however, that Québec is replete with three-way (and some four-way) races, so the seat projection in Québec is less reliable than usual.

The Liberals are also projected to be in a tight contest with the Conservatives for winning the BC popular vote. However, they are favoured in only half as many seats as the Tories.

Today's posting schedule is roughly as follows:
- Overnight: Projected winner in each riding
- Day: Guide to election night
- Day (if time allows): Roundup and comparison of projections around the web
- Around 9:00-9:15pm ET: Updated projection based on Atlantic results


Jeremy Akerman said...

I see Nanos's wrap up poll (2,400 ) gives the Grits 39.1%. Could that put them into Majority territory? I note that Harper needed 39.6% to get a majority of 24 seats.

Also, can I ask how your turnout adjustment worked in the Ontario election? I seem to recall that all the "likely voters" polls were wrong and that Frank was right on with his "all voters".

Many thanks. Am very grateful for all your work.

Anonymous said...

I like that Teddy on Politics is forecasting a Liberal victory in Victoria ... which doesn't have a Liberal candidate.


Election Watcher said...

@Jeremy: Harper didn't "need" 39.6% - that gave him an 11-seat cushion. Probably 38.5% would have been enough for him. The Liberal vote is less efficient, so I think they do need to hit 40% for a majority (unless their opponents' vote collapses in the right places).

I did not follow the Ontario election, but looking at the polls, the turnout adjustment would have been counterproductive. That's why my adjustment isn't as big as the actual CPC advantage in 2011: one never know whether it's going to materialize. (Although I should point out that it might not be a Conservative thing as much as an incumbent thing - think also 2004 and 2006 federal elections.)

@Anonymous: Awkward indeed... Also I'm very skeptical about the majority projection with that popular vote.