title: A cluster randomized trial evaluating electronic prescribing in an ambulatory care setting.
abstract: BACKGROUND
  Medication errors, adverse drug events and potential adverse drug events are common and serious in terms of the harms and costs that they impose on the health system and those who use it. Errors resulting in preventable adverse drug events have been shown to occur most often at the stages of ordering and administration. This paper describes the protocol for a pragmatic trial of electronic prescribing to reduce prescription error. The trial was designed to overcome the limitations associated with traditional study design.
  
  
  METHODS
  This study was designed as a 65-week, cluster randomized, parallel study.
  
  
  METHODS
  The trial was conducted within ambulatory outpatient clinics in an academic tertiary care centre in Ontario, Canada. The electronic prescribing software for the study is a Canadian electronic prescribing software package which provides physician prescription entry with decision support at the point of care. Using a handheld computer (PDA) the physician selects medications using an error minimising menu-based pick list from a comprehensive drug database, create specific prescription instructions and then transmit the prescription directly and electronically to a participating pharmacy via facsimile or to the physician's printer using local area wireless technology. The unit of allocation and randomization is by 'week', i.e. the system is "on" or "off" according to the randomization scheme and the unit of analysis is the prescription, with adjustment for clustering of patients within practitioners.
  
  
  CONCLUSIONS
  This paper describes the protocol for a pragmatic cluster randomized trial of point-of-care electronic prescribing, which was specifically designed to overcome the limitations associated with traditional study design.
  
  
  BACKGROUND
  This trial has been registered with clinicaltrials.gov (ID: NCT00252395).
authors.affiliation: Institute For Clinical Evaluative Sciences and The Clinical Epidemiology Unit, Center For Health Services Sciences, Sunnybrook Hospital, Ontario, Canada. merrick.zwarenstein@ices.on.ca
authors.forename: Merrick F
authors.initials: MF
authors.lastname: Zwarenstein
authors.forename: Katie N
authors.initials: KN
authors.lastname: Dainty
authors.forename: Sherman
authors.initials: S
authors.lastname: Quan
authors.forename: Alex
authors.initials: A
authors.lastname: Kiss
authors.forename: Neill K J
authors.initials: NK
authors.lastname: Adhikari