Updates
October 18, 2015 Second update today (8:10pm PDT) with the latest polling figures. These are the last polling figures to be released this election, so our current projections will remain until we update the map post-election with the actual results! (And see how well the polls, and our simple vote-swing model, performed...)
October 13, 2015 New polling figures, and a big functionality update. Along with a variety of tweaks and improvements, you can now zoom into a riding and get more details on its voting “history” (remember, the 2011 results are hypothetical!) and the former, pre-2013 ridings that make it up.
October 1, 2015 Added coastlines and major lakes to the map.
September 23, 2015 Initial launch! We’re still planning some more features, including a riding view. In the meantime, we’d love to hear your feedback: contact@plotandscatter.com.
Methodology
2011 election “results”
The 2011 “results” shown in this visualization are not the actual results of the 2011 election, as detailed below.
Redistribution of electoral districts
In the 2011 federal election, there were 308 ridings. As required by the Constitution, the 2013 Redistribution of Federal Electoral Districts redrew most riding boundaries and added 30 new seats to account for shifts in Canada’s population. British Columbia, Alberta, Ontario, and Quebec received new seats.
Transposition of votes
As part of this process, Elections Canada performed a transposition of votes. Effectively, this transposition represents a “what-if” scenario: what if the 2011 election were re-run, but using the new riding boundaries of the 2013 redistribution? (For more detail on the methodology of this transposition, visit their site.)
We used these transposed results as a baseline for the 2011 federal elections in this application. Therefore, the 2011 “results” shown here are the results we could have expected had the previous election been held with the new ridings.
2015 projected results
Our projections for the coming election are based on polling averages for each province, applied to the vote in each riding, as described below.
Provincial polling averages
The polling averages for each province are from the CBC Poll Tracker, maintained by Éric Grenier of ThreeHundredEight, and are used with his kind permission. More information on Mr. Grenier’s methodology may be found on his website.
Seat predictions
Although individual seat predictions are also based on Mr. Grenier’s provincial polling data, they are generated using our own algorithm. Therefore, they are not identical to those found on the CBC Poll Tracker or ThreeHundredEight.
Our algorithm compares the 2011 vote share on a provincial level to the projected provincial vote share using the CBC Poll Tracker polling averages data. The difference between a party’s vote share in 2011 and its polling vote share is then calculated. This difference (or swing) is then applied to the party vote in every riding in the province.
For example, in 2011 the Conservative Party received roughly 45.6% of the vote across all of British Columbia. At the time of writing, the Conservatives are polling at roughly 31.3% in BC. The swing in Conservative support is therefore 31.3 - 45.6 = -14.3. Our algorithm reduces the 2011 Conservative vote share in every riding in British Columbia by 14.3% to determine the projected 2015 Conservative vote share in that riding.
This process is repeated for every party in every province. Should a party’s vote share fall below 0% by this method, it is set to 0%. The winner of a riding is subsequently the party that has the highest support in that riding.
Note that this algorithm is very simple. It does not (currently) account for such effects as incumbency, varying regional party support within a province (though presumably the 2011 results already partially reflect this), or the power of star candidates.
Disclaimer
Please keep in mind that these projections are not necessarily an accurate reflection of voting intentions or actual results, and that there may be inaccuracies in the original data or their transformation.
Credits
Data sources
Electoral boundaries were mapped using data from Natural Resources Canada.
2011 election data were originally scraped from Elections Canada. They are also available for download here.
Polling averages for each province are from the CBC Poll Tracker, maintained by Éric Grenier of ThreeHundredEight.
Tools and frameworks
Boundary information in shapefile format was transformed into GeoJSON and TopoJSON using ogr2ogr and TopoJSON.
The map and graphs were generated using D3, with additional code adapted from TechSlides and Mike Bostock.
Side panel plugin from CodyHouse.
Comments
We’d love to hear your questions, comments, or feedback. You can reach us at contact@plotandscatter.com.
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