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,…

This report builds on and extends existent research on population invariance to new tests and issues. The authors lay the foundation for a deeper understanding of the use of population invariance measures in a wide variety of practical contexts. The invariance of linear, equipercentile and IRT equating methods are examined using data from five…