The BC election is officially on Saturday October 24th. However, many people have already voted by mail. Elections BC has statistics about the number of mail-in ballots requests, how many got returned already and the advanced polls turnout. They obviously won't tell us who those votes were for but I believe we are seeing some strong trends that will help us make sense of the results on Saturday.
First, let's look at who requested a mail-in ballot. I plotted the percentage of registered voters by riding against the projected voting intentions (based on my projections; I could have used the 2017 results for almost identical correlations). See the results:
In average, about 19% of RV have asked to vote by mail. Whether they'll all receive their ballots on time and will be able to return them by mail is a different question (note: if you have your mail-in ballot but haven't sent it back already, it's likely too late and you should drop your ballot yourself to one of the authorized locations by Elections BC). As we can see, ridings where the Liberals are projected to be high have had a much lower rate of requests for such mail-in ballots.
Elections BC said that while over 700,000 mail-in ballots have been requested, only 177,000 have been returned so far. Given that the 2017 election had just shy of 2 mio voters and I think it's reasonable to expect a lower turnout this time around, I think it's safe to assume that about half of the votes will be cast by mail. Which means we'll only have the results of half the votes on Saturday since Elections BC cannot start counting the mail-in ballots until 2 weeks after the election (that's the law). This is a very important element that people will need to keep in mind on Saturday when we start getting results.
We can also see the pattern of mail-in ballot requests by region where Vancouver Island is high (27%) compared to Metro Vancouver (21%) and the Interior (13%). We obviously always run the risk of ecological fallacy when using aggregate data to infer individual behaviors. We actually saw that during the referendum in 2018 where ridings with more young voters were also the ones who were voting more, yet the final results showed younger votes actually voted less. So I'll have to look into it more.
Does it match with the polls? Insights West was showing that Liberals voters were more likely to declare their intentions to vote in-person than NDP and Green voters. It also showed that older voters seemed more likely to vote in-person. Research Co. was showing that while half the voters planned to do so by mail, it was actually the 55+ who were declaring their intentions to do so. So we have contradicting evidence here. However, both polls were showing that among the people who had already voted, the NDP was ahead.
What about advanced in-person voting? According to Elections BC, 305,789 votes have been cast during the first 3 days (and it climbs to 380,000 if we include the fourth day but Elections BC hasn't updated their pdf yet). Over 600k voters had chosen this option in 2017. I don't believe we'll beat this number since many preferred the mail-in ballots route this year.
Do we see a trend in advance voting? Yes and this time, it's more positive for the Liberals. See below:
So it seems that this is consistent with Liberal voters preferring to vote in person while NDP voters would rather do it by mail. The BC Green party should be happy with both measures and they might be getting out their vote more than what the polls have indicated.
By the way, the correlation between mail-in turnout (measured by requests) and advance turnout is -0.04, so there isn't much of a correlation there. It's really when we look at each party that we see the negative correlation. I was expecting to see a negative correlation as people choosing to vote by mail might have been the ones who would have voted in advance otherwise. That might not be true then or other things are happening at the same time.
What does all of this mean? On Saturday, the votes of the day (and advance polls) will likely favour the BC Liberals (depending on the ratio of mail-in ballots received and advance turnout) and we'll need to keep that in mind. On the other hand, if the Liberals are in trouble based on Saturday results only, then we could just go ahead and call the election for the NDP.
Just a final word: I expect Saturday's results to be, overall, more favourable to the BC Liberals than the full results. So if we look at the province-wide percentages, the Liberals will be higher than expected. However, at the riding level, the bias might not be that clear cut. Indeed, if we do a regression where we control for both the projected voting intentions and the regions, the voting intentions aren't significant anymore (although it's not far to be for the Green). What it means is that the distinction between mail-in and in-person might have more to do with the region than the parties. So, on Saturday, we'll get more votes from the Interior than the Island but within a region, if we look at an individual riding, we might get approximatively accurate results. With the caveat that the Green might likely get a lower same-day votes than mail-in and advance ones (which is also consistent with the idea that small parties simply get less votes from the undecided and late switchers).
