Quite often my students will come to me and say “I have a really cool idea for an algorithm”. Most of the time, after hearing the student out, I will make suggestions about something similar but different to try.
The only reason I can do this is that, in most cases, I’ve already tried something similar to what the student is proposing — sometimes quite a few years earlier. Rather than make the student go through a month or six of pain, frustration and failure, I draw upon my own past experience to steer the student toward an approach that is much more likely to produce a positive initial result.
None of these experiences upon which I am drawing are publishable. You won’t find them in the literature under my name or under anybody else’s name. These are the research failures, the approaches that at first seem plausible but which prove, after hours of hard work, to be dead ends.
It’s a shame that there is no academic forum for sharing this valuable lore. You don’t get published for reporting things that do not work.
On the other hand, the very fact that you cannot find out these things on your own means that we professors are a valuable part of the process. I don’t know if this is good in the larger sense, but it certainly helps me to feel useful.