Hey guys,
I thought you might find this link useful: http://grad.uwo.ca/faculty_staff/financial_support/compensation.html. It distinguishes between the "Graduate Research Assistant" (GRA) and "Research Assistant" (RA). GRA is the research you are doing your Professor, and it is directly related to your thesis work. RA might be the research not related to your thesis, for example working for your Professor on a side project OR working for other Professor(s) from your University. GRA is not an employment, and its sole purpose is financial compensation:
To assist his/her student financially; to bring the student up to the guaranteed level of funding as stated by SGPS or the Department.
On the other hand, RA is valid employment.
What I mean is that if a Western student asks HR to write a letter detailing employment as a GRA, she is not going to get anything useful for immigration. On the other hand, if she has valid RA experience, not related to her thesis work, she may get a sensible letter from the HR. I'm not sure how these two experiences are called in other schools, but it should be similar due to the nature of work of PhD students.
Apparently, CIC is interested in the RA, not GRA. So IMHO, what hadikhan64 received is a request to explain how much time was spent on the thesis work ("GRA"), and how much time was spent on other research ("RA"). The reason GRA is less valuable than RA is that you HAVE to do it to get a degree, while RA is more voluntary and up to you. That's why most universities cap the maximum time you can work as a RA at 20 hours/week---because in addition to that, you have to do your thesis work.
If you ask me, I think this is ridiculous: You are getting this NOC 4012 experience anyways, no matter if you work as a RA or GRA. But apparently CIC officers really go by the book and want to distinguish the two.