CAIPS is acronym of "Computer Assisted Immigration Processing System”. CAIPS includes all the determinations made by a visa officer evaluating your file, in addition to concern the Canadian visa officer may have on your file.
It is at all times a good idea to ask for the CAIPS notes on your file if processing of your immigration case is taking longer than likely. For instance, most probably Citizenship and Immigration Canada is waiting for information from your side and you by no means received the request. Or maybe the visa officer has a concern about the authority of a document but you were not at all informed.
CAIPS let you to see concerns with your application which you can rapidly deal with by communication with the office managing your immigration application.
If you are called for an interview you should obtain your CAIPS which will likely disclose why the interview was called and which concerns the Canadian visa officer will discuss with you.
Citizenship and Immigration Canada (CIC) will send CAIPS to a Canadian address or to a spokesperson in Canada. If you are not residing in Canada there are some firms who will get CAIPS for you for a fee.