The Shulgin Rating Scale (or "quantitative potency scale") is a simple scale for reporting the subjective effect of psychoactive substances at a given dosage, and at a given time. The system was developed for research purposes by the American biochemist Alexander Shulgin, and published with co-authors Ann Shulgin and Peyton Jacob, III, in a 1986 issue of the journal Methods and Findings in Experimental and Clinical Pharmacology. It was later described in the Shulgins' popular 1991 book PIHKAL: A Chemical Love Story.[1]