1. 1086Methodological challenges using routine aggregated data in a primary care implementation trial on opioid prescribing. (2nd September 2021) Authors: Farragher, Tracey; Alderson, Sarah; Carder, Paul; Willis, Tom; Foy, Robbie Journal: International journal of epidemiology Issue: Volume 50(2021)Supplement 1 Page Start: Record Type: Journal Article View Content: Available online (eLD content is only available in our Reading Rooms) ↗