Overall, 46 per cent of respondents thought Trudeau won the debate, while 37 per cent felt Conservative Leader Stephen Harper emerged victorious.
Only seven per cent thought NDP Leader Tom Mulcair came out on top, while 10 per cent had no opinion of who won.
The findings are based on 14,812 respondents who participated in Vote Compass between Sept. 28 and Sept. 29.
The Sept. 28 Munk Debate on foreign policy was the third and final English-language debate of the election campaign.
Touching on issues such as the country's military role in the war in Iraq and Syria, Canada's response to the refugee crisis and the country's economic relationship with the U.S., the debate at Toronto's Roy Thomson Hall produced some of the scrappiest exchanges between the three main party leaders on this campaign.
The citizenship question
In one of the night's most memorable clashes, Trudeau criticized Harper's support of legislation that can strip Canadians convicted of terrorism-related offences of their citizenship.
Trudeau said it was a slippery slope if the prime minister has the capacity to withdraw a person's citizenship.
Harper was unmoved by the attack, saying, "Why would we not revoke the citizenship of people convicted of terrorist offences against this country?"
Mulcair, meanwhile, chided both Harper and Trudeau for their support of C-51, the government's anti-terrorism bill, which the NDP believes lacks oversight of the country's security forces and is not doing enough to tackle the root causes of extremism.
"Never forget that in Mr. Harper's failed Bill C-51, which was backed by Mr. Trudeau's Liberals, there was nothing on de-radicalization here at home," Mulcair said.
Vote Compass respondents across a variety of categories — from age to income to education — felt Trudeau won the debate.
The only category where he and Harper came close was when the respondents were broken down by gender.
Forty-four percent of men thought Trudeau won, as opposed to 41 per cent who felt Harper did.
Among female respondents, 49 per cent thought Trudeau won, while only 31 per cent felt Harper did.
Clifton van der Linden, director of Vox Pop Labs, which developed Vote Compass, says a possible reason why such a small proportion of those who watched the debate considered Mulcair the winner is that the audience was skewed towards Liberal and Conservative voters.
Only 15 per cent of the respondents identified as NDP voters.
Developed by a team of social and statistical scientists from Vox Pop Labs, Vote Compass is a civic engagement application offered in Canada exclusively by CBC News. The findings are based on 14,812 respondents who participated in Vote Compass between Sept. 28 and Sept. 29.
Unlike online opinion polls, respondents to Vote Compass are not pre-selected. Similar to opinion polls, however, the data are a non-random sample from the population and have been weighted in order to approximate a representative sample. Vote Compass data have been weighted by geography, gender, age, educational attainment, occupation, religion, religiosity and civic engagement to ensure the sample's composition reflects that of the actual population of Canada according to census data and other population estimates.
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