I came across this thread today.

Why not use the third derivative?

It has a very good discussion both in the comments and in the answers, yet it was closed as off-topic because it is about numerical optimization. This is very puzzling to me. We have quite a number of threads about optimization, and a whole tag dedicated to it.

Optimization clearly plays a large part in classical statistics (e.g. logistic regression) and modern statistics (e.g. neural networks).

Would anyone involved with closing this question care to comment on why it was closed?

  • 7
    $\begingroup$ Where to draw the line? Good question. How about questions on say eigenvalues or inequalities? Both arise in many branches of statistical science, but unless there is a statistical core to such questions, it would be the same boundary determination problem. $\endgroup$
    – Nick Cox
    Aug 31, 2018 at 16:52
  • 6
    $\begingroup$ One factor: as machine learning questions have grown to be a larger part of the site, at least some questions related to optimization have become less borderline than they were -- some questions that might have quickly closed say 6 or 7 years ago might not close at all now. $\endgroup$
    – Glen_b
    Aug 31, 2018 at 23:27
  • 1
    $\begingroup$ FWIW I edited the question and voted to reopen... $\endgroup$
    – amoeba
    Sep 2, 2018 at 21:58
  • $\begingroup$ @amoeba I had initially voted to re-open at the time that I posed this question, but I'm no longer convinced that was the correct action. The question is marginally on-topic, and there is a reasonable consensus that this question is on the wrong side of the line. I can accept that! $\endgroup$
    – Sycorax Mod
    Sep 3, 2018 at 0:16
  • 1
    $\begingroup$ Shouldn't we move the thread to another place instead of closing it? The question is not bad. It doesn't need editing but instead it needs a different place. $\endgroup$ Sep 3, 2018 at 20:57
  • $\begingroup$ See also stats.meta.stackexchange.com/questions/2990/… $\endgroup$ Sep 4, 2018 at 8:34

1 Answer 1


At the moment this question appeared, I asked the OP to indicate how it was related to statistics but got no response. The thread is indeed interesting and many can see implicitly its potential applications to statistics, but on the face of this evidence it was correctly closed.

Note that this thread is still available, still searchable, and people can still comment and vote on it: its closure just means additional answers will not be forthcoming.

FWIW, I was not among those who voted to close. That's probably because the community did the deed first.

  • 5
    $\begingroup$ I suppose it is telling that the post only has the optimization tag applied to it. $\endgroup$
    – Sycorax Mod
    Aug 31, 2018 at 19:00
  • $\begingroup$ Isn't optimization central to both statistics and machine learning? Aren't the concepts of training/learning/estimation basically synonymous to "optimization"? I don't understand why would you discourage people from asking such questions. $\endgroup$
    – Digio
    Sep 6, 2018 at 11:01
  • 3
    $\begingroup$ @Digio Nobody is proposing anything like that. Optimization comprises far more than the methods used in statistics. My answer is rooted in the basic fact that we do not field questions unrelated to statistics or machine learning. $\endgroup$
    – whuber Mod
    Sep 6, 2018 at 12:43
  • $\begingroup$ It's hard to draw the line. While it is true that optimization methods go beyond statistics, they could all be applicable to statistics. On the level of basic research there are constant efforts to adapt or invent new optimization methods for the purpose of estimation/training. In my perception, this makes optimization a related topic en par with simulation. $\endgroup$
    – Digio
    Sep 6, 2018 at 12:51
  • 4
    $\begingroup$ @Digio One flaw in that argument is that if it were valid you could draw all of mathematics and much of the sciences as well as a great deal of philosophy into the mix of on-topic questions, too. I don't find it at all difficult to draw the line: if the application to stats and ML is not apparent, then I ask the OP to explain how the question might be related to stats and ML. If they can tell us, then it's on topic. This works not only for optimization-related questions but for all questions. $\endgroup$
    – whuber Mod
    Sep 6, 2018 at 13:10
  • 4
    $\begingroup$ " this thread is still available, still searchable, and people can still comment and vote on it: its closure just means additional answers will not be forthcoming." -> closing a question allows users to vote for deletion. $\endgroup$ Sep 7, 2018 at 7:56
  • 1
    $\begingroup$ @Franck Thank you for adding that--it's a good point. Currently there is little risk of that thread disappearing for such a reason. On CV, at least up to the present, so few people vote for deletion that I believe few threads have ever been deleted by means of such votes (and those were easy decisions). $\endgroup$
    – whuber Mod
    Sep 7, 2018 at 13:47
  • 1
    $\begingroup$ I did not vote to reopen, in fact in comments to my answer to the question I noted that I thought it was off-topic. I think that something so specific to a particular optimization technique, and not in such a way that it is related to statistics, is really off topic. Something like "why don't more maximum likelihood estimation algorithms use Newton's Method?" would relate to a specific optimization technique but be on-topic. I thought it was a question well worth an answer, OT though it may be, but being well worth an answer isn't the relevant criterion. $\endgroup$
    – jbowman
    Sep 10, 2018 at 2:12
  • 1
    $\begingroup$ Gold star to @whuber, if they can articulate how it applies to stats or ML, then it is on topic. Agreed. $\endgroup$ Sep 18, 2018 at 17:10

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .