Greetings, great comment / question. I tend to have basic "3 star" criteria.
1 is missing some criteria (0)
2 meets criteria (85)
3 exceeds criteria. (100)
I have the following criteria. A post should 1. answer a question or meaningfully engage a topic, 2, provide original ideas, 3 use specific page-cited examples from class readings to back up / demonstrate ideas. This makes students dig deeper into the readings (or videos or activities) to keep making sure they are not just giving opinion, but backing up their ideas by recalling and using the information from class.
If a student meets criteria, they get the 2 star mark (or about an 85). If exceeds, a 3 star (or 100). and so on. Then, I roughly average out the grades of the posts to get a basic discussion grade. Of course, if a student only has 2 star marks, but many of them and engagd well, they might get a 90 overall discussion grade, or if they have an excellent post, but too few posts, they might get a lower grade. But the loose criteria of 1, answers question, 2 provides original insights, 3 backs up ideas with cited examples from class materials. acts as a good guide for me and for students seeking to meet requirements and gain most from discussions.
That's just my approach. Hope it's helpful. Thanks for good question.
