The research identifies the shortcomings and develops a new methodological approach to analyzing the effectiveness of intelligent decision support using big data and AI. The method (hierarchical procedure) by T. L. Saaty serves as the foundation of this new approach. Using statistics from the top 20 countries most actively employing big data and AI in 2023, the authors tested their approach using Russia as an example. The authors evaluated the effectiveness of intelligent decision support using big data and AI in Russia in 2023 using alternative approaches. The evaluation results were compared to identify differences between the approaches. As a result, the authors identified the advantages of the new approach. These advantages include better adaptation to the context of the Decade of Action, ranking the results of implementing intelligent decision support practices by their contribution to achieving the SDGs, and more accurate (technological instead of financial) cost measurement, enabling its application by mature digital economy organizations. The new approach advances the theory and methodology of analyzing the effectiveness of intelligent decision support, which constitutes its fundamental value. The use of the new approach by digital economy organizations will allow them to apply big data and AI as intelligent decision support technologies more reasonably and flexibly and increase the effectiveness of their application in management, which is the practical significance of the author’s approach.