It depends, lots of these experiments result in better bounds on theories. LUX for example pushed down the cross-section for WIMP dark matter below the previous measurement. That in itself is an advancement, with implications on what theories for dark matter are possible.
I was at a conference this morning and heard results from a highly anticipated clinical study, with millions of dollars in NIH funding. The results were disappointing for me and some others in the field, but I think that it's better to have the negative result than to not know what is best for patients given our current techniques.
Indeed, but unfortunately the lack of positive results is not a negative result in itself... This is when explaining a megaproject to the funders starts to become harder and harder.