A seat projection model prepared by political scientist Kennedy Stewart suggests that if the May 12 vote resembles recent public opinion polls, the B.C. Liberals will win another majority.
Stewart predicts the Liberals will win 56 seats, with New Democrats taking the remaining 29 seats.
The Simon Fraser University researcher’s model relies on averaged results drawn from five public opinion polls conducted since January. All five surveys were conducted prior to the launch of this campaign. Stewart said he will update this April 24 projection as new polling data becomes available.
“Projecting seats in single member plurality systems is a notoriously difficult exercise,” he warned.
For example, Stewart’s model predicts that if the B.C. Liberals win 49 per cent of the popular vote, then they’ll take 56 seats. Change the popular vote, and Stewart’s equation will change the seat projection. So if the Liberals were to win only 43 per cent of the popular vote – as a March poll by Angus Reid suggests – then they would claim only 43 seats. Or if the Liberals were to win 52 per cent of the popular vote – as an April poll by Mustel Group suggests – then they could dominate the chamber with 67 seats.
“Seats are not proportionately awarded in a single-member plurality system, meaning vote shares and seat shares do not necessarily match,” Stewart said.
For example, in 1996 the NDP won only 40 per cent of the popular vote, but nonetheless carried 52 per cent of the seats (39 of 75).
“This is mostly due to how votes are distributed within ridings. Using the 1996 example, the NDP won many of their 39 seats by very slim margins where the B.C. Liberals won their seats by wide margins. In other words, that year’s NDP vote was much more efficiently distributed than the Liberals vote,” Stewart said.
Likewise, as detailed in a paper released by SFU's Centre for Public Policy Research:
In 2001, the Liberals won 58 per cent of the vote and carried 97 per cent of the seats.
In 2005, the Liberals won 46 per cent of the vote and carried 58 per cent of the seats.
“These often lopsided single member plurality systems results make it difficult to use public opinion polls taken during elections to predict election outcomes,” Stewart said.
Kennedy’s regression model works by plotting a historical correlation between votes and seats for the B.C. Liberals, then applying that formula to future results. The model assumes that the NDP will claim all seats not won by the Liberals.
“This technique does not work for every single member plurality system, but works in BC because it is almost a pure two party system,” Stewart said.
This type of model does not consider local conditions that could shape certain ridings, such as the presence of exceptionally strong independent or third-party campaigns.
Monte Paulsen reports for The Tyee.