A prevalence study was done to audit prescriptions dispensed from 50 community pharmacies in southern Ontario. For each claim, the written information on the prescription was compared with the electronic information submitted to the ODB database. The sampling frame comprised pharmacies from communities in southern Ontario (Hamilton/S toney Creek, Ancaster/Dundas, St Catharines/Niagara Falls/Welland/Grimsby, Burlington/ Mississauga and Toronto). From a list of all 957 pharmacies in these jurisdictions, a random sample of 183 was contacted by mail and invited to participate. To enhance participation rates, $50 was offered to compensate for the time spent preparing the prescriptions and aiding the research assistant. ventolin inhaler

Within each pharmacy agreeing to participate, approximately 100 prescriptions dispensed between July 1, 1998 and December 31, 1999 and insured by the ODB were chosen randomly (by the research assistant) and reabstracted. Approximately equal numbers of prescription records from each month were chosen to control for any potential seasonal effects.

When a prescription is dispensed, the name of the patient, the prescribing physician and directions for the use of the medication are typed into a computer database. This information is used to create the label on the prescription and this record is the claim sent to the central ODB database. With some systems, the physician’s numeric identification is printed on the label but on other systems this information is only included in the computer record. This meant that the physician’s billing number was unable to be verified systematically.