BC referendum post-mortem: why were the polls so wrong?

I'm a little bit late for this analysis but you know how it is with Christmas and all.

The results for the referendum on electoral reform in BC were pretty shocking. While literally every single poll published before, during or right after the campaign had the two options pretty much at 50-50, the current system won with over 60% of the votes!

I guess this is fitting that, in a year that has been terrible for the polls (massive underestimations of the winner in Ontario and Quebec), we would also get polls be very off for a more uncertain exercise. Still, it doesn't make the results any less shocking. Beyond the polls, I really can't explain how a mail-in referendum with a simpler option (MMP instead of STV) with the active support of two of the three main parties wouldn't at least do better than in 2009.

So, why were polls so wrong? If you are expecting a clear cut answer in this article, you should stop reading. The short answer is still: I don't know. But I can try to provide some conjectures. If you don't have time to read, here is a point summary:

- Polls were wrong everywhere but especially wrong in the Lower Mainland
- It could be because polls didn't reach non-English voters enough as PR got really destroyed (and was overestimated) in the suburbs
- People aged 18-34 did vote more than usual but it wasn't enough for PR to win

Also, I'll ignore the magical polls published after the results (one from Research Co. and one mentioned by Ipsos) that somehow had FPTP clearly winning. I can give the benefit of the doubt to Ipsos since they were actually providing numbers to the NO side, even though I couldn't explain why Ipsos would have had a better methodology than other firms as Ipsos hasn't historically performed better. But for Research Co, they literally had another exit poll before and it was still mostly 50-50, so give me a break. Also, I should mention the exit poll from Angus-Reid, published right after the official results were made public. This exit poll had the two options pretty much at 50-50 but Angus-Reid made sure to use a headline hiding this fact. I found it amusing.

Anyway, I think the biggest discrepancy between results and polls can be observed regionally. Polls mostly all showed the same pattern: PR was ahead on Vancouver Island and the Lower Mainland while FPTP was clearly ahead in the Interior. The table below shows the polling average (same weight to every poll; Playing with weights doesn't make much difference) and the actual results.

Polls were overestimating PR everywhere but the bias is especially strong in the Lower Mainland. Is it because polls didn't correctly reach non-English speakers? Is that why Ipsos did better? Maybe.

If you look at the results by ridings, you see that PR won where we thought it'd (in some very urban Vancouver ridings) but it got destroyed way more than expected in most of the suburbs.

As for the general overestimation of PR, one easy explanation is that undecided ultimately chose the status quo. This would make sense but doesn't match with the fact that polls kept showing a 50-50 race as the campaign went on (and the number of undecided decreased). Exit polls (from Angus-Reid or Research Co, or even my own) were also good for PR and had no undecided. Ipsos mentioned on Twitter that FPTP was around 60% the whole time. So this theory really doesn't match with the numbers.

If we look at the second exit poll from Research Co (the one where they magically got the right results all of a sudden), we see that while BC Liberals voters did vote, as expected, to keep FPTP (with a margin even higher than expected), NDP and Green voters didn't remotely support PR as much as what the polls were showing. Polls had these voters over 70% in favor of PR but the exit poll only show PR at around 60%. So while I'm skeptical of a poll that all of a sudden got the right results, this might be the explanation: the BC Liberals got their vote out more and managed to convince more people while the NDP clearly didn't motivate its suburban votes to vote YES.

Polls had shown that this referendum was heavily split with regard to age with the 18-34 clearly in favor of PR while the 55+ were incredibly opposed to it. Regression-based analysis (with the final numbers) still shows what I had been saying: the turnout was higher in ridings with more young voters (relatively speaking, especially compared to 2017). Elections BC doesn't provide us with the results by age but I suspect that the NO won among the 55+ even more than what the polls were showing while the 35-54 most likely ended up voting NO as well despite the polls showing otherwise.

By the way, my measure of when a riding received the ballots (see previous blog posts about it) is still there and significant with the final numbers. If PR had lost by a tiny margins, I feel this should become a big issue. But given the margin of victory for the NO side, I guess we can forget about it even though this is troubling.

During the campaign I tried various methods to estimate the results (age, region or party based). I liked the method based on past votes the most as I thought this was the best "one variable" method available, one that would capture other effects as well (vote is correlated with region and age too). So I re-did these estimations and compared my results to the actual ones, riding by riding. Obviously my method was biased overall  since I had PR slightly ahead, but I'm more interested in finding patterns of where the method was more wrong. By the way, the overall correlation between estimated % for PR and actual ones is 0.83, so not too bad.

I found that the method was overestimating PR in ridings in the Lower Mainland and on the Island (and/or underestimating FPTP in the Interior). I was underestimating PR in ridings with more voters aged 18-34 and with a bigger share of English speakers. Maybe here is the most interesting piece of information: the method was underestimating PR in ridings that had a higher turnout this year but it was overestimating PR in ridings that had a higher turnout last year.

All in all, I maintain what I was saying: this referendum motivated more voters aged 18-34 to vote. I'm not saying the turnout in this age group was actually the highest of all age groups, but it was definitely higher than in previous elections. And this group likely voted for PR by a healthy margin. But that just wasn't enough to allow PR to actually win. The YES campaign (as illustrated by Horgan's performance at the debate) was weird. I gave them the benefit of the doubt during the referendum as I thought that they maybe had data showing it was working, but in hindsight, it was a mistake. Focusing on the young, progressive vote (it's "lit") was a bad idea. These voters were going to support PR anyway. What the YES side had to do was convincing older voters that PR was a good idea. Offering three systems without fully defining one just opened a giant door for the NO side who could spend 30 days saying it was "too complicated" or too risky. It also seems the NO side was successful in making this referendum feels "rigged" even though I don't really see valid reasons behind this argument.

Proportional representation is now a dead in BC for many years (as it should be after such a loss). Hopefully Quebec leads the way next year and adopts PR. Legault has mentioned he doesn't intend on doing a referendum and while I believe one could be successful in Quebec, I also never thought PR would get less than 40% in BC. So no referendum might be the safest way to get PR, although I feel a referendum is most likely needed nowadays to change the electoral system... But I'm seriously tired of losing referendums! So go Quebec and go PEI next year!