Purpose: The purpose of this paper is to develop an analytical framework toward facilitating the quantitative measurement of interdisciplinary understanding regarding sustainable energy systems with an application in the area of capacity-building projects in higher education. Design/methodology/approach: The analytical framework is developed using the portfolio representation measurement approach in combination with a survey questionnaire. The subsequent assessment is carried out using the statistical measure of mean signed deviation to capture variation from an established baseline across the project group and visualized via radar diagrams. Findings: The results provide a quantitative assessment framework for evaluating the degree of interdisciplinary understanding in the project groups. The application of the framework to the DESIRE project indicates the most significant degree of variation across economic and regulatory dimensions of sustainability. Discrepancies in general and educational contexts are observed. Research limitations/implications: The exploitable value of the results is sensitive to the derivation of composite indicators of the dimensions defined as well as the survey design. The case study was carried out on an ex-post basis, potentially biasing the results reported and limiting their interpretability and theoretical value. Practical implications: The analytical framework can be used as a basis for assessing and engaging in discussions on interdisciplinarity understanding at the outset of capacity-building projects. Originality/value: The contribution of this paper is practical in scope and entails the development of a quantitative framework for measuring interdisciplinarity in the specific context of capacity-building projects in the field of sustainability research in higher education institutions.