The project delivered five core research contributions and several supporting methodological advances.
First, it demonstrated that policy optimality can be evaluated using only forecasts and impulse responses. These statistics are sufficient to detect and quantify deviations from optimal policy. The approach was applied to U.S. monetary policy from 1990 to 2022, showing that while deviations from optimality were typically small, some notable episodes—such as the early phase of the Great Recession—featured measurable departures from optimal decisions.
Second, the methodology was extended to allow historical comparisons of policy institutions over long time horizons. Applying the framework to 150 years of U.S. monetary policy revealed substantial improvements in policy conduct over the past three decades and provided a systematic comparison between different monetary regimes.
Third, the framework was adapted to measure policy makers’ preferences. A revealed-preference approach was developed to quantify “fiscal discipline” in the euro area, measuring how policy makers balance compliance with fiscal rules against macroeconomic stabilisation objectives.
Fourth, a comprehensive methodological review consolidated the sufficient-statistics approach and demonstrated its application to the evaluation of European Central Bank performance.
Fifth, the project introduced a novel econometric method—innovation-powered instrumental variables—which improves the precision of causal estimates when credible identification strategies suffer from low statistical power. This method reduces uncertainty in estimated policy effects by combining narrative identification with parametric information in a robust way.
In addition, the project produced advances in inference for dynamic causal effects and structural vector autoregressions, strengthening the econometric foundations of policy analysis.
Overall, the action resulted in high-impact journal publications, advanced working papers under revision at leading journals, new econometric methods, and the development of policy-oriented analytical tools.