Tracking Shifts in U.S. Monetary Policy: Comparing Multiplicative Indicator Saturation With Three Alternatives

ABSTRACT This article applies Multiplicative Indicator Saturation (MIS), for automated coefficient break selection, to a Taylor rule estimated with real‐time data and the shadow federal funds rate from 1972 to 2025. MIS is compared with sample splitting by Fed Chair, Bai–Perron break tests, and Markov‐switching. MIS offers advantages by controlling for outliers and allowing parameters to vary flexibly over time. Across methods and specifications, several breaks emerge as robust, most notably Volcker's and Greenspan's appointments. Surprisingly, once interest rate smoothing is incorporated, no test rejects a constant policy ‘rule’ after 2000, despite this period's reputation as a ‘new discretionary era’.