My background: Doing a PhD in Canada, Biology. Also I've visited Australia and learned a bit about difference with UK, Australia and generally speaking european PhD.
My first question is what is the PhD defense failure rate in Canada?
(I'm not sure if I really want to know this).
In my field, I've never seen or heard about anyone failing. I've heard about such things in other fields, but as a surprising evil.
How much weight is put on the defence in Canada?
Well, it's the pinnacle of the PhD, but I think it's mostly seen as a ritual. No advisor is supposed to let his/her student defend if he/she is not ready.
Is there anything that examiners usually look for in PhD defence in
As I've never examined a thesis, this is only guess from the multiple defences (>10) in biology I've seen. They generally try to push the student further into the interpretation, they ask questions about why the student chose this method and not this other. They will also look at how the different chapter fit together and are linked by the general introduction and discussion.
I would tell you "no worries". Canadians are almost as laid back as Australians. Every researcher I know who is going to a defence in another country expect difference and will make enquiries before the defence.