The facilitation of critical thinking is one of the most frequently discussed potential benefits of the asynchronous online discussion environment, but many studies have reported that it does not occur to any great extent. This study investigated the effect of information provided to students on the facilitation of their critical thinking outcomes as perceived by their instructors. The study examined the effect of three main types of information that can be given to students at the commencement of the discussion: information about the purpose of the discussion activity, information on how discussion postings will be graded, and examples of graded postings. It also explored the impact of preparatory sessions aimed at helping students understand the concepts of critical thinking. The study found that information on the purpose of the discussion activity and how postings would be graded were important in the facilitation of critical thinking, while the results for examples of graded postings and preparatory sessions were inconclusive. (Contains 7 tables.)