Abstract: Collaborative problem solving (CPS) is one of the 21st century skills identified as a critical competency for education and workplace success. Students entering the workforce will be expected to have a level of proficiency with both cognitive and social-emotional skills. This paper presents an approach to measuring features and sub-skills associated with CPS ability and provides a methodology for CPS based performance assessment using an educational problem solving video game. Our method incorporates K-Means clustering to evaluate and analyze the feature space of the CPS evidence that was gathered from game log-data. Our results illustrate distinct participant clusters of high, medium and low-CPS skills proficiency levels that can help focus remediation efforts.