Knowledge elaboration plays a critical role in promoting knowledge acquisition and facilitating the retention of target knowledge in online collaborative discussions. Adopting a key-term-based automated analysis approach, we proposed an indicator framework to measure the level of knowledge elaboration in terms of coverage, activation, and equitability. An interactive web-based tool was developed to provide a multidimensional view of students' knowledge elaboration, allowing teachers to have a real-time, in-depth understanding of students' mastery of domain knowledge. Using students' discussion posts on a problem-solving task as the data source, a case study was conducted, and the results showed that the proposed methodology was effective in examining group knowledge elaboration in online collaborative discussions.