One key question in the study of the European Union has always been the extent of Commission discretion. We take the discretion index, typically used by principal–agent scholars to measure the Commission’s designed discretion, to measure its actual discretion. Commission designed discretion can today be computationally generated with sufficient accuracy across all secondary acts. The study of designed discretion thus reaches considerable maturity. Therefore, we argue that scholars should prioritize studying Commission actual discretion. We present a systematic and transparent investigative technique based on the discretion index, which we use as a roadmap to guide our empirical investigation. The index facilitates the accumulation of knowledge across policy areas and time by providing exact values for Commission discretion. We illustrate our approach with the Development Cooperation Instrument.