Parity Across Time

Byron Weber Becker and Antony Hodgson

Groups of voters are best represented when the candidate they vote for is actually in office.

The following graphs compare, for various groups of voters, the share of time their preferred candidates spend in office representing them with that group’s share of the vote. In a fair system, those two shares would be approximately equal and lie near the “parity line” running from the lower left to the upper right.

Obviously, that’s not the case. Some groups of voters are severely under-represented. For example, Liberal voters in Ontario’s Haldimand-Norfolk riding contributed more than 30% of the votes over time, but have never had their preferred candidate represent them.

Others are over-represented. For example, NDP voters in Manitoba’s Elmwood-Transcona riding contributed less than 47% of the vote but have been represented nearly 90% of the time over the last 13 elections. In other settings, voters have contributed less than 50% of the vote but had their candidates in office 100% of the time!

In the graphs that follow, hover over the dots to see riding name, percentage of votes, and percentage of time in office. Following the graph is a table with more data, including the elections included. More information is on the Details page.

This data covers the modern electoral era, Parliaments 31 (1979) to 43 (2019).