McGowan 1976.

Methods	STUDY DESIGN: ITS Risk of Bias: LOW
Participants	PROVIDERS: all physicians in the hospital PARTICIPANTS: all patients in the hospital CLINICAL PROBLEM: patients requiring antibiotic treatment SETTING: single university hospital in USA
Interventions	FORMAT: Intervention: restrictive by expert approval and probably by review and make change Intervention Function: restriction DELIVERER: specialist physician COMPARISON: usual care DESIRED CHANGE: decrease excessive
Outcomes	PRESCRIBING: Choice: grams of chloramphenicol (thousands), data are also presented for other drugs (ampicillin, nafcillin, and cloxacillin)
Notes	FINANCIAL SUPPORT: Funding: grants 5R01‐A1‐23, 2T01‐AJ‐08, and IT01‐Ai‐447 from the National Institute of Allergy and Infectious Diseases. Competing Interests: no information ADDITIONAL DATA: no response from authors to request for additional data
Risk of bias
Bias	Authors' judgement	Support for judgement
Intervention independent (ITS) ?	Low risk	Data over 8 years, 4 years pre‐ and 4 years postintervention
Analysed appropriately (ITS) ?	Low risk	Re‐analysed. Not done in original paper: comparison of means (uncontrolled before‐after).
Shape of effect pre‐specified (ITS) ?	Low risk	Done, intended effect was decrease in primary outcome, and point of analysis was point of intervention.
Unlikely to affect data collection (ITS) ?	Low risk	Done, data were from routine systems and unlikely to change over study period.
Knowledge of the allocation adequately prevented(ITS)?	Low risk	Done, data were from routine systems and unlikely to change over study period.
Incomplete outcome data addressed (ITS) ?	Low risk	Done, data were from routine systems and unlikely to change over study period.
Free of selected reporting (ITS) ?	Low risk	Done, data were from routine systems and unlikely to change over study period.
Free of other bias (ITS) ?	Low risk	No other apparent biases found.