Collaboration is generally recognized as a core competency of today's knowledge economy and has taken a central role in recent theoretical and technological developments in education research. Yet, the methodology for assessing the learning benefits of collaboration continues to rely on educational tests designed for isolated individuals. Thus, what "counts" as evidence of learning does not correspond to current best practices for teaching, and it does not reflect what students are ultimately expected to be able to do with their knowledge. The goals of this paper are to give an overview of the research conducted in several fields of work related to collaboration, propose "a framework for the assessment of cognitive skills (such as science or math) through collaborative problem-solving tasks," and propose several statistical approaches to model the data collected from collaborative interactions. This research contributes to the knowledge needed to support a new generation of assessments based on collaboration.