This work proposes a comprehensive research agenda to empirically evaluate the real-world impacts of the European Union’s Digital Services Act (DSA) on combating online disinformation. It provides background on the DSA’s context, mechanisms, timeline, and expected effects on platforms to situate the need for rigorous impact assessment. A detailed legal, technical, psychological, behavioral and ethical critique reveals meaningful gaps in the DSA requiring ongoing regulatory refinement and oversight. Most critically, the paper puts forth an encompassing framework spanning computational analytics, interviews, ethnography, surveys, discourse analysis and mixed methods to rigorously assess the DSA’s multi-dimensional effects on complex factors enabling disinformation proliferation. Priorities include evaluating notice-and-takedown efficacy, advertising transparency improvements, risk assessment outcomes, oversight integration, and procedural shifts in platform governance. Coordinated efforts between researchers, regulators and platforms are needed to address methodological challenges around isolating DSA impacts amidst an evolving EU regulatory landscape, constrained data access from platforms, and difficulties generalizing findings across the sociotechnical diversity of platforms and national contexts in EU Member States.