Dual-member mixed proportional

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The dual-member mixed proportional (DMP)^[1][2][3] voting method is a mixed electoral system using a localized list rule to elect two representatives in each district.^[4] It is similar to other forms of mixed-member proportional representation but differs in that all representatives are elected locally in small districts, rather than requiring separate list seats to be filled in large regional or nationwide districts. In the first step, one seat in each district is awarded to the candidate with the most votes, as with first-past-the-post voting rules. In the second step, underrepresented parties are assigned secondary seats in the districts in which they won the most votes, which creates an overall proportional result.

DMP was invented in 2013 by a University of Alberta mathematics student named Sean Graham.^[5] The system was intended as a possible replacement for single-member plurality (SMP) in Canadian national and provincial elections. After campaigns to adopt mixed-member proportional representation (MMP) or the single transferable vote (STV) had been defeated in a number of Canadian provinces (see 2005 British Columbia referendum, 2005 Prince Edward Island referendum, 2007 Ontario referendum, 2009 British Columbia referendum), the intent behind DMP was to gain broader acceptance by retaining the key features of SMP. These features include a one-vote ballot, small districts (unlike with STV), and a single tier consisting only of local representatives (in contrast to MMP).^[6]