ETE said:
The margin wasn't that bad. He lost because of the refugee thing, which i really don't support admitting them without proper security screening. I think the conservative had a good plan, they were just too stubborn to listen to people and make it clear to people.
http://www.cbc.ca/news2/interactives/results-2015/
56% vs. 35%. Alexander lost by 11972 votes.
For a competitive riding (Unlike rural prairies where cons could get like ~70%) and a high profile candidate, it's pretty high.
Canadian elections for some reason has unusually high counts of close elections. I was watching another riding in Regina, NDP wins by 143 votes (0.856%)
https://en.wikipedia.org/wiki/List_of_close_election_results
Though it's true that Ajax is not a cons strong hold.