Hi sharedknowledge,
Consider this: Do you think the immigration officers knows more about your subject than you do? It is only a confidence game that's all.
All the comments about experts in your field being present in your interview is a lie. CIC does take the help of expert consultants for technical jobs, however there are only few of them in Canada and they don't go flying off to conduct interviews.
You have been selected for an interview, because there is a doubt in the immigration officer's mind about some information you have provided in your application (e.g. some experience letters seem like they are copy pasted from, CIC website with some changes or your ties to your home are very strong (e.g. you are an only son) which leaves a doubt you will not mentally settle in Canada or your name is flagged (e.g. you and someone on terror watch-list have similar names)); or the second scenario where you are not getting enough points and the immigration officer wants to use his discretionary points to push your application. If it is the first scenario, then you don't even have to worry if everything in your application is truthful. The interviewer will just read your body language and in some cases will throw difficult and technical questions your way, but this is only to see how your react. However if you are in the second scenario, then you may face a difficult battle and in many cases you may be denied immigration.
It is better to order your GCMS notes to see why you have been selected for an interview.
Regards,
