A record of forecasts vs. results can be found below - the barometer has yet to make a wrong call in 11 federal and provincial by-elections.
What the By-Election Barometer is
The By-Election Barometer tracks all scheduled and upcoming federal and provincial by-elections. The percentages shown in the charts represent margins, colour-coded according to the standards adopted by this site. The first set show the results of the last two elections.
The second set of margins are those that the projection model churns out when each regional/provincial poll is applied, using the same system as ThreeHundredEight's standard seat projection model. These are a way to demonstrate what might be expected in the riding, based on regional trends. The rolling 30-day average calculates an unweighted average of the last 30-days of regional polling.
The third set of margins, when available, represent the results of actual polls of the riding that have been released.
Finally, ThreeHundredEight's Forecast is calculated by taking the projected range of results from the average of the last 30 days of polling, including any polls done for the riding itself, and comparing how the ranges for each party overlap. The amount of overlap that potentially puts a party in a position to win is then tallied, the result being a percentage "chance" of that party winning the riding.
A Strong result means a 95% to 100% chance of winning, Likely is a 75% to 94% chance, Lean is a 60% to 74% chance, and Toss-Up means the chances of a party winning are 59% or less.
The Wildcard section describes any factor that could make the result unpredictable.
What it isn't
The By-Election Barometer is not a poll, the section titled "Margin after application of swing from regional polls" is not a list of riding polls, and the 30-day average is not a projection. By-Elections are notoriously hard to call, and the Barometer is not a tracking of actual voting intentions. The forecast is also not an opinion. As always, I am tied to what the numbers show.
A by-election in Labrador is scheduled for May 13. By-elections have yet to be called in the Ontario ridings of Windsor-Tecumseh and London West and the riding of Cartwright-L'Anse au Clair in Newfoundland and Labrador.
Duncan has won Windsor-Tecumseh and its predecessor ridings by large margins in the past, though that shrank to only 10 points in the 2011 election. With the Liberal vote having dropped in most polls since the election, the New Democrats could be able to wrest the riding away.
The only riding-specific poll released so far, by Forum Research, gave the New Democrats 42% of the vote to 32% for the Liberals on a generic ballot. The Tories finished third with 19% (the poll was conducted Feb. 7 and surveyed 403 residents of Windsor-Tecumseh).
The poll shows that a candidate like Sandra Pupatello, on the other hand, could retain the riding for the Liberals. Pupatello won't be running, but that doesn't mean the Liberals won't be able to find someone of similar calibre to carry the party banner. It would help if they find a strong candidate, as otherwise the riding could be lost to the NDP..
Forecast history: Was STRONG NEW DEMOCRAT on March 4, became LIKELY NEW DEMOCRAT on March 8. Became STRONG NEW DEMOCRAT again on April 5, and back to LIKELY NEW DEMOCRAT on April 19. Became LEAN NEW DEMOCRAT on May 3, and TOSS-UP NDP/OLP on May 17.
Bentley won the riding for the Liberals over the last three elections, winning majorities twice and still winning by 16 points in the last election. Before Bentley, the riding voted PC during the Harris years. It is possible it could go that way again.
But the Liberals have the advantage of incumbency, and their numbers have been improving. It makes London West a Likely Liberal hold.
But a riding poll by Forum Research (Feb. 11, 724 surveyed) which gave the Progressive Conservatives 34% of the vote to 30% for the Liberals and 28% for the New Democrats suggests it could be more competitive, though the poll is now somewhat dated.
Forecast history: Was TOSS-UP (OLP/NDP/PC) on March 4, became LEAN LIBERAL on March 8, and LIKELY LIBERAL on April 5. Returned to TOSS-UP (OLP/NDP/PC) on April 26. Became LIKELY LIBERAL on May 3.
This should be an easy win for the provincial Liberals. The party is still trailing the PCs and NDP by a wide margin province-wide, but the Tories have dropped significantly and they have traditionally been the main opponent to the Liberals in the riding.
Jones has represented Cartwright-L'Anse au Clair since 1996, and has won with huge majorities taking more than 70% of the vote in the last two elections.
The Liberals have held the riding since 1975, after the Labrador Party held it for one term. The riding would seem to be a Liberal stronghold, but Jones has represented it for so long that it is difficult to know for certain whether it is still a primarily Liberal riding or just a Jones riding. She was, after all, first elected as an independent against the incumbent Liberal candidate.
It seems unlikely the Tories are in the running. Their support has plummeted in recent months. The New Democrats, however, have been surging and have led in a few of the last provincial polls. The NDP only took 2% of the vote in 2011, the first time they had run a candidate in the riding since the 1990s. But now that Jones won't be on the ballot, how many voters would consider going with the NDP this time around? If the New Democrats find a great candidate - and the Liberals don't - they could have a shot. They will certainly be gunning for the riding, as a win would vault them ahead of the Liberals in the seat count in the House of Assembly.
But because of the numbers that Jones put up in the last election and the current trends, the model considers this riding to be a Strong Liberal seat. I don't suspect anything will happen to change the model's mind.
Forecast history: Has been STRONG LIBERAL since Jones's resignation.
Morris has voted in a Progressive Conservative MLA for more than a generation, and Tallieu won the riding by a huge margin in 2011. Just with the riding's history, it would be considered a Tory lock.
That the PCs have improved their position in the polls over the last few months make the riding in even easier hold for the Progressive Conservatives. Barring some disaster, a PC MLA will represent the riding after the next vote.
Forecast history: Has been STRONG P.C. since Taillieu's resignation.