In my Master's program, some professors used rubrics to help the students decide how much effort they wanted to put into the assignment based on how much time they might have. The level of participation was connected to a specific grade. The rubric clearly stated that if you wanted an "A," then these were the expectations. They did this specifically for discussion forums. An "A" might be "significantly respond to three of your cohort's discussion points." A "B" wopuld required two responses, etc.
