Redistribution 2012, which gave 15 new seats to Ontario, 6 to Alberta, 6 to BC and 3 to Quebec, was based on Statistics Canada's population estimates for July 2011, as of December 2011. However, those estimates were based on the 2006 Census and subsequent birth/death/migration statistics.
Today, Statistics Canada published revised population estimates that incorporate data from the 2011 Census. Using the revised population estimates for July 2011 and applying the legislated formula, we see that:
- Ontario and BC should each have gotten one fewer seat;
- Alberta and Québec should each have gotten one additional seat.
Even though, as explained above, the number of ridings in each province was based on the 2006 Census, the new districts were drawn based on the 2011 Census. The reason is that boundaries are adjusted based on actual census counts, available soon after the census, while each province's number of seats depends on population estimates, which take into account census undercounting and take over 2 years to produce.
By the way, the use of population estimates for redistribution is new: under the old law, actual census counts were also used to determine each province's seat allocation.
At some point in the coming months, Elections Canada will publish the results of the 2011 election transposed onto the new districts. I'm hoping to resume posting seat projections after this information becomes available. (Transposition has already been done by others, but since I'm quite busy with work these days anyway, I'll wait for the official numbers.)