This study proposes taking into account the group matrix in the analysis of specific patterns of academic behaviour: the students’ concern for an adequate preparation, reflected in their academic results, and their participation in didactic activities. The group matrix is defined as a unitary system with three interrelated dimensions: inter-knowledge, communication and cooperation in a social group (formal or not), the system being at the basis of the entire dynamics of that group. The three dimensions of the group matrix (inter-knowledge, communication and cooperation) correlate with the students’ academic results and with their participation in learning activities. The practical relevance of this investigation consists in offering a new basis for the study of desirable academic behaviour and didactic group activities. The theory and practice of the group matrix has a broader applicability, potentially for every group where the inter-knowledge, communication and cooperation dimensions can be identified and assessed.