CWCI's latest update on Independent Medical Review, derived from IMR decision letters from 2015 through 2021, measures changes in IMR volume, shifts in the mix of services reviewed; changes in IMR response times; regional variations; and IMR uphold rates by medical service category. The study also looks at the distribution of prescription drug IMRs and uphold rates by drug category; the proportion of IMRs involving medical service request modifications among six treatment categories; and the concentration of IMR activity among high-volume physicians named in IMR letters.