The interview, which is ordinarily attendant the same event as the test, is primarily a documents-check interview, pursuant to which the applicant is instructed to present the original of those supporting documents copies of which were submitted with the application. This aspect of the interview is done for all applicants and involves more or less perfunctory questions related to the interviewer's task to verify the authenticity of the documents, verify the applicant's identity, and compare the original documents with the copies submitted and with information in the file, including details in the application itself. Again, this part happens to all applicants and is often (if not most often by a big margin) perfunctory, barely taking a couple minutes or so.
There are some mandatory questions, not many and these too are usually perfunctory, regarding particular requirements, such as questions related to prohibitions (any criminal charges? for example). These too are brief and take a very minimal amount of time (unless, of course, an issue comes up, such as if the applicant has been arrested since applying or such).
In addition to that, most applicants are asked a few casual questions related to information in their application or otherwise in the file. These too tend to be perfunctory and brief, related to verification of details, the interviewer paying as much attention to the applicant's demeanor and body language, manner of speaking, as to the content of the answers themselves. Thus, the interviewer's focus is on assessing the credibility of the applicant, on one hand, while at the same time screening the details for incongruities, inconsistencies, or outright discrepancies.
Thus, as Blueboy1980 observed, and experienced, the applicant can anticipate some general questions, such as about employment or confirmation of travel history, and such.
All that adds up to just a few minutes. The interview can be remarkably quick. Mine went so quickly that despite my intent to make note of every question, the next question was asked before I could barely complete my answers and then it was abruptly over, done.
That is the typical, most common interview. BUT more than a few report a more in-depth interview, a significantly longer, more probing interview.
Beyond what is described above, the nature and scope of the interview may be far more intrusive, more probing, and sometimes even severely exacting if not combative.
. . .
All that said, about the possibility of a severe, probing interview, the most common experience reported is a brief, perfunctory, mostly friendly Q&A.
The vast majority of applicants have no reason to worry about the nature or scope of the interview. There is no indication that interviewers go on fishing expeditions or arbitrarily employ gotcha traps. The vast majority of questions asked are simple to answer. For the applicant who has honestly and accurately provided information in the application, the questions should be a breeze.
