de Champs 1994.

Methods	STUDY DESIGN: ITS Risk of Bias: HIGH
Participants	PROVIDERS: physicians on a paediatric ICU PARTICIPANTS: all patients on paediatric ICU CLINICAL PROBLEM: neonates requiring intensive care including empirical antibiotic treatment SETTING: paediatric ICU in a university hospital in France
Interventions	FORMAT: No valid prescribing data. Restrictive: change in antibiotic policy from gentamicin to amikacin DELIVERER: specialist physician COMPARISON: usual care DESIRED CHANGE: decrease excessive
Outcomes	MICROBIAL: monthly incidence of infection with multiresistant Enterobacter cloacae
Notes	FINANCIAL SUPPORT: Funding: grant from D.R.E.D. (Direction de la Recherche et des Etudes Doctorales). Competing Interests: none declared ADDITIONAL DATA: no response from authors to request for additional data
Risk of bias
Bias	Authors' judgement	Support for judgement
Intervention independent (ITS) ?	High risk	Only 7 months' pre‐intervention data, so secular/seasonal changes possible. Very complex case definition with no information about how this was applied reliably across the pre‐ and postintervention periods.
Analysed appropriately (ITS) ?	Low risk	Re‐analysed. Not done in original paper: comparison of means (uncontrolled before‐after) with t‐test.
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) ?	Unclear risk	Case definition included clinical interpretation.
Knowledge of the allocation adequately prevented(ITS)?	Unclear risk	NOT CLEAR because of case definition
Incomplete outcome data addressed (ITS) ?	Unclear risk	Availability of all data required for the case definition not documented.
Free of selected reporting (ITS) ?	Unclear risk	Not clear, no information about changes in sampling or testing protocol over study period.
Free of other bias (ITS) ?	High risk	Microbial outcome risk of bias: Unplanned intervention: implementation of change in response to emergence of gentamicin‐resistant E cloacae; Case definition:infection from clinical or screening isolates combined with 7 clinical criteria and 5 additional laboratory criteria assessed by a resident paediatrician and a consultant microbiologist and verified by a consultant paediatrician. Reliability of this outcome measure not clear. Other infection control measures: well documented, no changes during the study period