This study is concerned with the challenge of understanding what factors may influence students' higher level knowledge construction. We defined higher level knowledge construction occurrences as the sum of the number of phases II to V measured using Gunawardena et al.'s (J Educ Comput Res 17(4):397-431, "1997") interaction analysis model. This paper is organized into two studies. In the first study, we examined the relationship between the frequency of higher level knowledge construction occurrences and group size, as well as the duration of the online discussion. Data were collected through online observations of 40 discussion forums. We found a significant positive relationship between group size and the frequency of higher level knowledge construction occurrences. However, there was no correlation between the duration of the online discussion and the frequency of such occurrences. In the second study, we examined the types of student facilitation techniques used. A further analysis of the data was conducted--of the 40 forums, 14 forums with higher incident rate of higher level knowledge construction occurrences were identified. Fourteen less frequent forums were then "randomly" chosen from the remaining forums. We found significant differences in the frequency of four student facilitation techniques employed between the more frequent group and the less frequent one. The results of this study suggest that using these four techniques more frequently may promote knowledge construction in asynchronous online discussions.