Should I add references to a conference poster

This may be a somewhat discipline-dependent question (and you don't specify yours), but I can say that I have often seen references on posters -- and just about as often not. When I have seen them, they have generally been in the lower right-hand corner (for most left-to-right languages, the last place anyone generally looks). Not uncommonly they are in smaller type than the rest of the poster, to save space.

I think this depends a lot on the nature of and venue for the poster. Are you talking about a conference poster that accompanies an article in the proceedings, and the proceedings are published by the time of the conference? If so, then one of the main purposes of your poster is to get people to read your paper. Your paper already has all the relevant references, and so (in most cases) there's no need to waste valuable space repeating them on the poster.

If you are talking about a poster that does not accompany a published paper, then you should use your best judgment about whether references serve a useful purpose. If the material you present has a particularly strong relationship or dependency on past work by yourself or others, and you think your audience might want to consult this past work for themselves, then by all means provide references. To save space, I would make these only as long as necessary to identify the referenced works.

Another possibility might be for you to leave the references off the poster but include them in a handout for interested visitors. At all my poster talks, I print off several A4-size copies of the poster and hand them out to people who wander by to have a look. My posters don't normally include references, but if I thought they were necessary, I'd print them on the reverse of the handout.

You're quite likely to end up with a few points that probably should be cited. For example previous work as background to why you did your work, or how you interpreted it. In this case there are a couple of reasons to refernce the work:

• For the interested reader (who may even be more interested in the backgreound than in what you did).
• As a courtesy (and in the vast majority of cases that's all it is) to the people who have worked in the field before. This is particularly useful if the authors of an important piece of work might be at the conference.

However, there's not much room for such background on a poster, it should be nearly full of your own work (another reason why a cited, very brief, summary is good). So you shouldn't have many references. My last poster had 2. The one before had 3, of which 2 were self-references to the two methods I was showing off on the poster.