In the wake of a very close election in BC it is worth considering the effect that strategic voting might have had. The rise of the Green party had many leftists in the province concerned that the Greens and NDP might split the vote and allow the Liberals to win several ridings. After the election, it is possible to check to see which ridings might have changed parties had there been more or less strategic voting. A look at the results shows that, because the election was so close, strategic voting could have changed the result. It is important, however, not to overstate strategic voting’s impact. Had the seat difference between the Liberals and NDP been in the range of 5-10 seats, it is unlikely that such voting would have mattered.
The first question that arises with respect to strategic voting, is whether the NDP could have taken more seats from the Liberals had more Green supporters switched their support to the NDP. To test this, I looked at the percentage of Green voters that would have needed to move to the NDP in order for the NDP to match the Liberals’ vote percentage in any particular riding. When doing this I assume that the remaining Green voters stick with the Green party.
The graph below shows that a large number of Green voters would have had to move to the NDP in order to have anything more than a minimal impact on the number of seats that Liberals won. The NDP would have added only two seats to their total had 20% of Green voters switched to them, and only 3 more seats had 40% switched. In addition to this, Green switching to the NDP would have increased the safety of two ridings, Coutney Comox and Mission Maple Ridge, that the NDP barely won and which could switch to the Liberals after absentee ballots are counted or after a re-count. The NDP would have had to win 80% of the Green vote in order to flip 10 seats. For this to happen, the overwhelming majority of Green voters would have had to both prefer the NDP to the Liberals and would have had to decided to vote strategically.
It is also worth considering the impact that individuals who strategically voted in this election might have had. To do this I looked at the number of NDP seats that the party would have lost had various percentages of NDP voters chosen to vote for the Greens instead.
This analysis also shows that strategic voting had a limited impact on the result. If the NDP lost 5% of its vote, it would only lose two seats. These are the two extremely close seats that may still change hands when absentee votes are counted, Courtney Comox and Mission Maple Ridge. If the NDP lost 10% of its vote, it would lose 3 seats, and if it lost 20% of its vote it would lose 8 seats. If 20%-30% of the NDP vote came from Greens voting strategically, strategic voting affected a large number of seats in this election. Otherwise, Green strategic voting only affected the outcome in couple of seats.
Because this election was so close, even things that had a small effect on election results mattered. When one or two seats that are decided by less than 1 percentage point make the difference between a majority and a minority government there are a large number of things that affect an election. In such a close race, strategic voting in close ridings matters. In Courtney Comox, Mission Maple Ridge, Coquitlam Burke Mountain, Richmond Queensborough, Vancouver False Creek, and Fraser Nicola the decision over whether to strategic vote mattered. In most other ridings, however, it likely did not.
This has two major implications. First, voters should be very careful to check the competitiveness of their ridings before strategically voting. In a close election, a strategic vote in a close riding can have a critical impact on the election result. In most ridings, however, a strategic voter may not be getting much out of such a vote. Second, moving to an electoral system such as a ranked ballot or run-off that allows voters to, in effect, cast a sincere and a strategic vote (by expressing multiple preferences on her ballot) are unlikely to change election results all that much. Unless 30% of NDP voters are actually Green supporters strategically voting for the NDP, there are few ridings where the Greens would be competitive under a ranked ballot or run-off system. Strategic voting is not a magic bullet that can fix the disproportionality of first past the post electoral system, nor is it a powerful force denying smaller parties like the Greens seats.