Have you considered answering a survey when submitting an entry? I think something like that (with or without a comment text area) might be the easiest way to quickly give an idea of what was done :

Did the team make the art during the course of the Jam? Yes/Most/Some/No

Did the team make the music and gfx during the course of the Jam? Yes/Most/Some/No

Did the team make the coding during the course of the Jam? Yes/Most/Some/No

Did the team make the design choices, note taking, 3rd party asset research if appliead during the course of the Jam? Yes/Most/Some/No (Yeah, the formulation of this one is weird, just left it because I think it's not completely irrelevant).

I am probably not the only one who don't really care about other people's answer to this (just a little bit the postive way, a bit curious and pleasantly impressed sometimes, never the opposite) but like to be transparent about what we've really done ourselves with my team.

If it's not convenient to set up  or you think it feels like too much policing then just ignore the suggestion of course.