Medication errors are a significant cause of mortality in hospitalized patients, and antimicrobials are the drug class most commonly implicated. Pre-approval antimicrobial management programs (AMPs) improve patient outcomes by guiding the prescribing of antibiotics. However, the interactions between AMP consultants and primary health care teams may be prone to errors in communication that limit the benefit of these programs. We will perform a retrospective cohort study to determine the effect of inaccurate communication of patient data (from physicians caring for patients to the AMP practitioners) on inappropriate antimicrobial recommendations. The quality of patient data recorded by the AMP practitioners will be judged compared to the patient medical record. A panel of experts will rate the appropriateness of the actual recommendations given by the AMP practitioner after reviewing the actual data associated with each case. Multivariate regression modeling will be used to evaluate the independent effect of any inaccurate communications on the risk for inappropriate recommendations, controlling for characteristics of the provider, patient, and AMP practitioner. The results of our study will be applied in a future intervention study, using clinical outcomes as an endpoint.