University of Tehran Journal of Solar Energy Research 2588-3097 11 3 2026 07 01 An Outcome-Based Coupling–Efficiency Framework for Evaluating Solar Expansion Performance 3267 3284 108724 10.22059/jser.2026.410866.1717 EN Ankur Gupta Institute of Business Management , GLA University, Mathura 0009-0003-1091-8069 Ruchika Kulshrestha Institute of Business Management, GLA University, Mathura, India 0000-0002-5188-9204 Journal Article 2026 02 09 Traditional measures of solar energy transitions primarily focus on investment growth and installed capacity rather than on whether policy-driven implementation delivers meaningful energy outcomes. This study provides an analytical approach for assessing solar energy expansion by focusing on realized outcomes rather than capacity growth alone. It examines the relationships among investment behaviour, policy signals, technology adoption, and deployment efficiency. The research offers two indicators, PIACI (Policy_Investment_Adoption_Coupling_Index) and CESA (Carbon_Efficiency_of_Solar_Adoption) based on cross-country panel data on 2010-2023 collected on a global energy and policy database. These metrics reflect both the effectiveness with which energy is produced, as well as the consistency of policy-based growth. The findings reveal substantial differences in national transition pathways through performance-regime analysis and the assessment of regime shifts. The findings indicate that moderate but stable coupling can prove more effective than aggressive but volatile expansion strategies and that strong policy coupling does not necessarily ensure efficient performance. The proposed framework will take renewable energy evaluation to a new level by combining the concepts of coupling, efficiency, and time dynamics to offer an effective instrument of evidence-based solar policy development. https://jser.ut.ac.ir/article_108724_2f5932f5d704b051a02ec3df618f6f34.pdf