Is it seriously being suggested that interviewing a candidate yields no more useful information than looking at a CV?
I respectfully disagree; I don't follow the reasoning that leads to that conclusion.
It may yield "useful" information depending on what you consider useful. What i referred to was, that the interview result does not have a significantly higher statistical correlation to the candidate's performance than does the CV alone, provided the CV is "good" and properly analyzed. I know, you find it hard to believe. And you are entitled to your opinions but note that i didn't express an opinion. I semi-quoted actual studies made. Next you will ask for references so here is one
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.169.9712. You won't find the outcome stated in a simple one sentence conclusion but you will find what i write below.
Let me elaborate. Competence in a topic (any topic) is built up over time by practicing activity in that topic
and getting feedback (critical this, otherwise the result is just false self-confidence) until the activites subject to that topic become in a fundamental way different mental processes from those of a novice. I won't go deeper into the psych theory behind this because it is perhaps not essential. Now, assuming people don't actually directly lie in their CVs or applications (there are ways to detect this also), a careful reader will be able to extract this information from the document. There are several key items that should be present and recognized and if they are, the interviewee just saying so or demonstrating ad hoc the same skill provides only limited additional info.
If you insist on having an interview with quizzes - and most don't have the courage to do without - here's a hint. When you present the quiz, arrange so that you can see the eye pupils of the interviewee during the performance. The are about as reliable as clockwork to indicate the level of mental effort. The pupil size is more or less directly correlated and varies almost instantaneously. Don't believe me? Then take a video clip on your handy phone of your own face when doing some mental arithmetic - say multiplying 2 digit numbers in your head. You might be surprised. Anyway, an expert will expend visibly less mental energy in solving tasks in his/her knowledge domain than will a novice and this difference is visible in the relative pupil size.
Finally, please don't take this as a recommendation to skip interviews altogether. More perhaps as a note and warning that most of us delude ourselves into thinking the interview is somehow a way to find an objective truth. It is not.
P.S. During my career i have hired between 150 and 300 people for employment and consultation assignments. Mostly programmers for various languages and environments, but other kinds of IT experts as well. Their personality was assessed in an interview in every case, but notably not a single time did i have them perform a quiz. Instead there were requirements on the format of CV such that the relevant ionfo was available and this system worked entirely satisfactorily. With hindsight, i could have skipped almost all of the interviews with no ill effect whatsoever...
It should be noted that there was absolutely no perceivable difference between these persons and those recruited by other means. Specifically the employment termination rate and causes was in line with the averages always.
Edit: typos.