Summary: Discussion forums are the main conversational tool built into Moodle for asynchronous classroom discussion. The following are some of the common ways that you can evaluate your student's work in Moodle Forums.
Option 1: Use Ratings: Ratings allows the instructor to provide an integer score for each post. To activate ratings in the forum settings you need to set the following two components in the forum settings:
Option 2: Manually add an item to the gradebook: This option allows you to enter grades directly into the gradebook (in one window or tab) while you read discussion posts (in another window or tab). The advantage is that you can use decimal grades (8.5) as opposed to integer grades (8 or 9). The disadvantage is that you must work in two windows.
Option 3: Use a rubric: This option allows you to use a specific rubric to grade forums.