There are periods during my galactic empire's inevitable ascendancy in which there are no systems for my science ships to survey, as we are already omniscient concerning our vast and glorious holdings.
During these periods, I can order each of my science ships to "Assist Research" at a colony until such time as they have real work to do.
However, there comes a time when we have learned all there is to be learned about all the galaxy's celestial bodies. Given that there is nothing left to be surveyed, I must decide if it is worth keeping the science ships around just to Assist Research.
How much do they help? What factors are involved? Do they boost just that one planet or my whole empire?