As part of the new MusicSpoke project, I've been spending time talking to composers and conductors and performers of all sorts. One of the ways that composers receive income is through a licensing organization like ASCAP or BMI. So, if we have a performance at a venue that is covered by the licensing agreement, we can receive compensation.
A major frustration on the part of composers is that we honestly don't know where our music is being performed. If our music is sold through a traditional publisher, the publisher just gives us a little note at the end of the year that says how many copies were sold. We actually don't even have a way to authenticate that.
There are certain venues (like primary and secondary education concerts) that are not covered by ASCAP and BMI. There are also a few other exceptions which you can read about here. If you are in a professional or University venue for your performance, the most helpful thing that you can do is contact the composer of the work you are doing and let him/her know that you are performing their work so that they can report it.
Right now, we at MusicSpoke are still learning about which problems need to be fixed. I can envision a type of publishing where the composer is automatically notified and put in contact with the performer or conductor. Until a better solution arrives, please help us out and get in touch when you do our work. In fact, we composers even like to be in touch when you are doing our work in a non-paying venue.