Parrish's lead fades days before Mississauga vote

Carolyn Parrish's lead in Mississauga's mayoral byelection has almost disappeared in the final days before the vote on June 10, according to polling data. 

While Parrish consistently led in six polls, published between April 17 and June 7, her lead among decided voters has dropped from being nearly double her closest competitor at one point to as little as one percentage point — and the race for second place may also be shifting.

The polls, conducted by a number of firms, have been evaluated by CBC's research team. You can find details about their methodologies at the bottom of this story.

A Pollara poll released this week found Parrish's lead over her second place challenger, Alvin Tedjo, among decided voters was just three points, which is within the margin of error. While Mainstreet's poll, released Friday, has Dipika Damerla in second, just a point behind Parrish among decided voters. Liaison's poll, also published Friday, has both Tedjo and Damerla tied a point behind Parrish.

Parrish's challengers can use these poll results to motivate voters to get out and vote in ways not possible in the early days of the race, said Dennis Pilon, a political scientist at York University.

"Polls are important because they don't just reflect the results, they also help to create the results," said Pilon. "Now the second place person can make a strong argument to their supporters, every vote is going to count."

Undecided voters, who are usually a mix of those not necessarily planning to vote and those still making up their mind about who to choose, may now decide the race is competitive enough that it's worth casting a ballot, Pilon said. 

He said campaigns may now try and use polls in their messaging to steal committed voters from their competitors.

"A bandwagon effect can occur as voters start to see a migration towards certain candidates," he said.

Two of the polls published this week — Pollara's and Mainstreet's — indicate close to a third of eligible Mississauga voters haven't yet decided who they will vote for. Liaison's last poll, meanwhile, suggests more voters have made up their minds, saying just 18 per cent indicate they are undecided.

Polls have changed over time

In April, multiple polls indicated many voters had decided on Parrish.

For example, a Mainstreet Research poll conducted between April 6 to 8 found 34 per cent of decided voters surveyed said they'd be voting for Parrish.

Parrish's next closest competitor in that poll, Dipika Damera, had 19 per cent support among decided voters. Stephen Dasko had 17 per cent and Alvin Tedjo had 11 per cent among decided voters. 

Later that month, Parrish continued to easily hold on to the top spot, with the support of 37 per cent of decided voters in a Liaison poll conducted April 29 to 30. Damerla received 20 per cent support among decided voters, Tedjo 17 per cent and Dasko 11 per cent in that poll. 

But nearly a month later, the polling picture changed.

Parrish's support dipped to 29 per cent among decided voters in a Liaison poll conducted on May 24 an 25, while Damerla's number rose to 24 per cent, Tedjo had 19 per cent and Dasko 12 per cent. 

A few days later, Pollara surveyed residents between May 30 and June 2. The results, provided to CBC News, indicate a further slip for Parrish, and a significant shift in the second, third and fourth place contenders.

Alvin Tedjo had moved into second place in the Pollara poll. Parrish received 27 per cent of support from decided voters, Tedjo had 24 per cent, Stephen Dasko had 23 per cent and Damerla was in fourth place with 20 per cent. 

Mainstreet and Liason's last polls, conducted this week, indicate the closest margins between a first and second place challenger seen in the race, with differences of a single point among decided voters.

In Mainstreet's June poll, 25 per cent of decided voters said they were voting for Parrish, 24 per cent for Damerla, 21 per cent for Tedjo and 18 per cent for Dasko.

Liaison's last poll results showed 24 per cent of decided voters choosing Parrish, while Tedjo and Damerla were tied at 23 per cent and 18 per cent chose Dasko.

Late shifting polls suggest race outcome uncertain

John Tabone, CEO of the Canadian Research Insights Council, which works to ensure high standards are followed in polling research, said it may have taken the candidates who weren't seen as the front runner longer to get their profile across, which may explain the recent shifts in support. 

Tabone said polls can provide voters "useful information when making a decision on who they want to support, to know where things are kind of stacking up," but he cautioned "these are getting a prediction of where voters are at a particular time."

He said election polls can shift a lot in the final days before the vote and the outcome is not certain in this race.

"A change or a statement by one of those candidates could make a difference in terms of whether they get a big bump or see a big decline," he said.

Here's the full list of who is running for mayor:

• Zulfiqar Ali.

• Diya Atassi.

• Brian Crombie.

• Dipika Damerla.

• Stephen Dasko.

• Jamie Dookie.

• Frank Fang.

• Xiaohua Gong.

• Winston Harding.

• Sara Iqbal.

• Syed Jaffery.

• Mohsin Khan.

• Mitchell MacEachern.

• Sinisa Mandrapa.

• Mike Matulewicz.

• Carolyn Parrish.

• David Shaw.

• George Tavares.

• Alvin Tedjo.

• Nathalie Xian Yi Yan.

A note on polling methodologies:

Mainstreet Research used the following methodologies:

The first Mainstreet Research poll referenced above was conducted using Smart IVR technology involving automatic telephone calls made to 887 Mississaugans between April 6 to 8. Mainstreet says the margin of error for the poll is plus or minus 3.3 per cent at the 95 per cent confidence level. 

The second Mainstreet poll was conducted using Smart IVR, among a sample of 1176 Mississauga residents on June 3 to 4. Mainstreet says the margin of error for the poll is plus or minus 2.9 per cent at a 95% confidence level. 

Liaison used the following methodologies:

The first Liaison poll referenced above surveyed a random sample of 914 Mississauga voters through IVR from June 4 to 5. The margin of error is plus or minus 3.24 per cent, 19 times out of 20.

The second Liaison surveyed a random sample of 907 Mississauga voters through IVR from April 29 to April 30. Liaison says the margin of error is plus or minus 3.25 per cent points, 19 times out of 20.

The third Liaison poll surveyed 933 Mississauga voters through IVR from May 24 to 25. Liaison says the margin of error is plus or minus 3.22 per cent, 19 times out of 20.

Pollara used the following methodology:

Using IVR, Pollara surveyed 606 eligible voters in Mississauga between May 30 and June 2. Pollara says the margin of error is plus or minus 4 per cent, 19 times out of 20.

A note from the CBC News research team: 

All of these polls used the IVR method to sample Mississauga voters. CBC's research team cautions that an exact margin of error can't be determined for this type of recruitment.