As with any grading system, there are various ways to do so. Whatever the method, just make sure your students clearly know your grading requirements. The following are some ways that others have graded on-line discussion. Grade on-line discussion as class participation. There are a variety of ways that professors use to grade these discussions, as there are for grading class participation.
Some professors give a grade for the number of times a student contributes to the discussion.
Others grade on the quality of the contribution and how students follow the guidelines for the discussion. Give a separate grade for on-line discussion. Student also attempted to appreciate dissent and complexity as incentives for new thinking. Give a grade for small group work. Have the members of small groups assess the other members' contributions.