Dual Member Proportional (DMP)

DMP in a Nutshell

Neighbouring pairs of ridings would be merged into two-member constituencies, except for the largest rural ridings, which would remain as single-member constituencies. Most candidates would run as pairs in the dual member districts, and voters would choose their preferred pair. The first seat in each riding is won by the primary candidate of the party that receives the most votes, while the allocation of the second seat takes into account local and provincial results.

Dual Member Proportional (DMP) is one of the three systems on the ballot in BC’s referendum.

DMP was created by Sean Graham in 2013. It was one of two proportional systems on the PEI plebiscite in 2016.

How it Works

With DMP, BC’s current single-member districts would be paired, to create half as many dual-member ridings. The BC Attorney General’s report recommends that a small number of the rural ridings remain single member ridings.

All candidates would run in their local dual-member district, and voters would choose their preferred pair of candidates.

The first seat in every district would go to the first candidate of the party with the most votes, while the second seat would be filled to create a proportional election outcome across the province.

An advantage of DMP is the simplicity of the ballot. Just like first-past-the-post, it is one X for voters.

You can learn more about method to allocate the second seat here: https://dmpforcanada.com/how-it-works/

There is an excellent video and a lot more information on DMP on Sean Graham’s DMP site.


In 2015, three parties - the Liberals, the NDP and the Greens, representing 63% of voters - promised that if elected, 2015 would be the last election under first-past-the-post.

The NDP and Greens promised to implement proportional representation. The Liberals promised to end first-past-the-post, listen to expert advice and follow evidence-based policy on electoral reform, and to "make every vote count."

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