Measuring knowledge convergence: Achievement similarity and shared knowledge in computer-supported collaborative learning

Learning in small groups may result in convergent knowledge outcomes or foster possible prior differences between learners. Few studies, however, measure convergence or divergence of knowledge as an outcome of small group learning. This contribution analyzes knowledge convergence/divergence as an outcome of learning in small groups with the concepts of achievement similarity and shared knowledge rooted in two different theoretical frameworks. Achievement similarity means that learners acquired similar amounts of knowledge regardless if they share similar knowledge. Shared knowledge means that learners acquired similar knowledge. In order to test application-oriented knowledge, learners had to individually apply concepts of a psychological theory in analyzing a problem case. Trained coders identified correct relations between theoretical concepts and case information. These data were used to compute both, achievement similarity and shared knowledge. A 2×2 factorial design was used (number of triads = 32; N = 96) to examine the following questions: (1) can theoretical concepts of achievement similarity and shared knowledge be measured independently and (2) to what extend are these measures of convergence sensitive enough to indicate effects of specific instructional interventions? We examined effects of two instructional interventions on achievement similarity and shared knowledge. Achievement similarity was conceptualized as difference between the amount of known theoretical concepts of an individual learner and the average of his or her group. As a measure for achievement similarity, standard deviations of learners within one group were used to indicate dissimilarity and multiplied by -1 to indicate similarity. Shared knowledge was measured as number of pairs within one group, which applied the same theoretical concept in the individual analysis of the problem case. Results show that the different instructional interventions significantly and independently affect both convergence measures. Validity and interpretability will be discussed against the background of theoretical approaches to learning in small groups.