The following article By Anthony Piscitelli and Jason Thistlethwaite was published in the Globe and Mail:
Ontarians are looking for direction on how to act during the COVID-19 pandemic. Prime Minister Justin Trudeau’s daily press briefings have had hundreds of thousands of views, and updates from Premier Doug Ford have been eagerly awaited by Ontarians looking for provincial direction on how to address the coronavirus.
While the guidance has been useful, when it comes to mask policies our Ontario government has unfortunately left the decision-making entirely up to local municipalities. Many local governments have stepped up to fill this policy void, but with clear evidence of the effectiveness of masks in reducing COVID-19 already available, more concrete leadership should have come from the province.
With the votes mostly counted and almost all seats decided, it is now possible to evaluate the election projections and predictions. For this analysis, I have used data from the CBC Canada Votes at 11:00 am on October 22, 2019.
Liberals won 157 seats. Overall, we can see that all the poll
aggregators except for Lean Toss Up underestimated support for the Liberals. All
the analysis-based projections also underestimated the Liberal support.
However, two of three polling firms Ekos and Mainstreet overestimated support
for the Liberals. Ekos was the closest to the Liberal projections missing by
one seat at 158.
The Conservatives won 121 seats. Every poll aggregator
projection, except for Lean Toss Up and @politicstacan, overestimated support
for the Conservatives. All three polling firms underestimated Conservative
support. Calculated Politics was the closest Conservative projection missing by
one seat at 122.
The NDP won 24 seats. Every projection overestimated NDP
support. Lean Toss Up and Mainstreet were the closest to the NDP at 25. The
Bloc won 32 seats and every projection except for Ekos and Mainstreet estimated
Bloc support. Calculated politics were closest to the Bloc at 34.
The Green party won three seats. Seven projections accurately
projected this result. The People’s Party of Canada won zero seats. Seven
projections accurately projected this result as well. One independent won,
fifteen projections predicted this result.
To evaluate the overall accuracy of the different projections two methods are being used. First, the projection for each party is subtracted from the actual seats won. The absolute value is then taken (i.e. if it is negative it is turned positive) and these values are added together. The second method involves taking the Sum of Squares difference. This is done by subtracting the difference between projection and result and squaring this value then adding these together. This value is then divided by 7 (for the 7 projections) and then the square root is taken to show the average difference between each individual projection. The results of the two approaches are relatively similar.
Mainstreet was the most accurate projection by polling firm
with Ekos close behind. Lean Toss Up was the most accurate poll aggregator, and
third most accurate. The Elections Prediction Project was the most accurate analysis-based
projection and fourth overall.
Part of the accuracy is determined as a result of the models
the polling firms and aggregators use to project the election. Some of the
differences in accuracy can also be attributed to how the polling aggregators model
the polls of the election.
When comparing how the poll aggregators did at projecting
the election Lean Toss Up once again was the most accurate only missing the
actual results by an average of one percentage point. It should be noted that some
of the poll aggregators did not share the projections for the PPC of Independents.
While individual models varied slightly in their performance. Overall, the aggregators, analysis-based projections, and polling firms should be satisfied with how they performed at projecting this election. All models predicted a minority government and most projected the Liberals would win the most seats.
*Updated at 1:00 pm to include the final Mainstreet seat projections