I got my Amateur Extra ticket some time ago. I was able to discover what my score was (the number of questions I got wrong). However, my examiner was not able to tell me specifically which questions I had answered incorrectly, and to this day it still irks me. Isn't the whole point of licensing academic, i.e., to make sure that operators are knowledgeable? I would like to have been able to go back and study on those questions where I obviously didn't have enough knowledge or might have been confused.
So why can't people who pass the test but got a few wrong learn which questions they got wrong? I am not asking for the right choice on the test, only the questions and the answers on the test, so I can go back and figure it out afterwards.
Having participated as a volunteer examiner in a few test sessions, I think there are a number of reasons this is the case:
We tend to quietly give the pass/fail results — and should offer the number wrong with an encouraging "you nailed it!" or "you were so close this time!" — as soon as we've finished processing them. Most of the time others are still taking their own tests. Discussing the questions/answers when they might be overheard would definitely not be appropriate in this setting.
The way the ARRLs tests are generated is randomized and they are graded using a key completely separate from the particular question set itself. When we check your answers we don't even know what the topic was, without finding back the test booklet. Since everything needs to be done in triplicate, the volunteers are usually busy enough keeping accountable with scoring and paperwork already.
Also, while we try to be approachable and congenial (and I haven't witnessed a case where an examinee became combative or even particularly disgruntled) the ARRL's VEC guidelines are very careful to guard both the authority and the objectivity/professionality of the examiners. Perhaps the ARRL feels the integrity of the testing process would be more at risk if there was too much discussion of the test itself?
Finally, in my understanding, the whole point of the "random questions from a published test bank" is to encourage knowing a wide body of knowledge or at least a full set of answers. If you failed the test, knowing what you got wrong may not help you anyway since the next test you get will likely have different questions anyway. (In fact, so long as they pay the fee again, examinees are welcome to retake a failed element during the same session. When you're on the line, luck becomes an element.) If you passed the test — well, now you're on your way to learning most of the material even better; "hands on" this time!
As to your question in the comments why it can't be an administered computerized test, I don't think that it's entirely due to the ARRL's culture. "We drove to the big city and then didn't get our callsign from the bureau until months had passed" nostalgia or not, tech has been a part of of ham radio for long enough.
I think it's a much more practical concern: our VE group and many others like it does not have a dedicated facility. We hold test sessions every other month in the basement of a Boy Scout office. Dealing with enough laptops or even tablets to service the dozens of examinees who show up would be a nightmare.
I can see your point definitely, but I think the process attempts to remain consistent with the past and prevents the examiners from being further burdened during the testing session.
Although, in the US, the ARRL is making the rules now (apparently), historically, the FCC examiners did NOT discuss the results of the tests. You were handed the questions and answer sheet, and after turning them in, were told if you passed or failed. It was not considered their place to potentially get into a discussion with the candidate (pass or fail) on the various topics. Even though one might presume that the current volunteer examiners might be more amenable to discussion (than the previous FCC guys), I think it's a good idea to separate the testing from the learning.
Unlike the ARRL, if you take your exam at a session given by the Laurel VEC, the VEs are not only allowed but encouraged to go over the missed questions with the candidates for exactly the reason you state; to help you learn the material.
This is true whether you pass or fail the exam.
(I am both an ARRL VE Team Liaison and Laurel VEC Team Lead.)