This isn't going to be easy to fix.  It's probably a bug in the Drupal Views module, and their usual suggestions for removing duplicate entries aren't fixing the bug.  I'm not even sure where to start with debugging it (Views is an incredibly complex module, and I'm not familiar with the code at all).

I'll see what I can do, but as this is comparatively rare compared to some other issues, it may have to be on the back burner.

Hey Bart,

I can see that many problems arise with the drupal backend. Have you ever thought about writing the site software from scratch?

if bart had a dollar every time someone has said that. the site would reach its goal.

Indeed.

This site exists because of Drupal.  As for whether I've ever considered rewriting OGA from scratch, the answer is absolutely not.  I don't have the time.

Also, you what you don't see here are people talking about the hundreds of things on this site that just work because of Drupal.  Things that I would have had to code myself (and likely never would have gotten around to in many cases). 

For the record, I'm aware that searching is broken.  I am planning on addressing it in a big way, and that involves a major rework of the search system.  If I have to write the code for that part of it myself, I'm prepared to do that.  Drupal is nice in that way -- it's pretty simple to drop in your own code.

In essence, the reason that I don't rewrite the site from scrach is the same reason that I'm not rewriting the little parts of it that don't work very well -- I haven't been able to find the time to do that.  Regardless, getting rid of everything because other people don't like Drupal isn't the solution.

Bart, I hear ya on the Drupal thing - I've tried coding for/with/against it before, and Views are a beast!!  Good luck!  Thanks for all you do!

In both of the cases reported by william.j (search caves of sorrow), the number of times it shows in the results seems to be related to the number of collections they are in.

For other duplicates, such as a bunch of results if you currently browse the latest 2d art search, the duplicates are related to the number of licenses assigned to each piece.

So the duplicates are probably caused by sql joins where the join condition matches multiple records. I'm guessing the joins will be the same for all of the possible search criteria (the above case is probably tags).