I sometimes find an article published in several conferences.
If similar material is published in different conference proceedings, how do I choose which one to cite?
I sometimes find an article published in several conferences.
If similar material is published in different conference proceedings, how do I choose which one to cite?
Normally you should cite the most recent version, which is probably also the most prestigious venue (normally republication is done while ideas are working their way up the prestige ladder). It's possible that only the earlier version contains the material you want to cite though, but unless that's substantially longer than a later version, then I would assume that means the author(s) have recanted that part, and you should probably mention that in your article e.g. "Bryson (1986) claims fish can fly (p. 253), though note later work does not reiterate this claim (Bryson 1991; Bryson 1993)."
It's a little unusual to have the same or even similar material published in different venues. First of all, you didn't say whether your area uses conferences as primary publication venues or not - I'm assuming it does, otherwise why even cite a conference publication.
In that case, what exactly are you citing in the article ? If it's a specific result (empirical, theoretical etc), then probably the oldest venue where it appears is the first occurrence of that result, and should be cited. If you're citing background material or motivation, then either the first paper that discusses the relevant motivation, or maybe a survey article ?
At any rate, the key is to understand exactly what you're citing the article for, and find the oldest occurrence of that concept.
You should have two goals in mind when choosing what to cite:
Give credit, by citing the first person to discover the result, in the form in which it was originally found
Helping the reader interested in looking the result up and learn it in more depth.
Either one of them can be more important than the other, depending on the type of your paper and of the context of the specific citation.
The two goals are often conflicting; for instance, #1 might tell you to use an obscure conference proceeding with a clumsy first version of the result, and #2 might suggest to use a clear exposition in a book by another author instead. You might want to go for a tradeoff instead and cite a newer paper by the first author with a better version of the result.
In any case, if your choice is backed up by either of these two rationales, or by a suitably weighted linear combination of them, then in my opinion no one can blame you.
On a number of occasions, I found myself knowing the author personally pretty closely, and would ask them which version they want me to cite. On other occasions, I would cite whichever source I read first, and just stick to that. People should not be cited five times for one idea; it is little of my business to untangle their political games of publishing the same stuff in different journals (a very common thing in the social sciences I mingle with), and I would do whatever works for me, not for them.
Cite all versions! I find this practice useful, because it gives me all the information that the author has. Ideally, you should explain the distinctions between different versions too.