Q–Q plot of the residuals between actual and expected antibiotic prescribing after adjustment for case mix. The y-axis represents estimated residuals of the 1962 practices’ antibiotic prescribing per 1000 patients per year. The x-axis denotes the theoretical normal distribution. Ten percent of high prescribers issued more than 155 prescriptions per 1000 patients per year above the estimated average for practices with a similar case mix. Due to Danish data regulations, the presented graph depicts mean values from merged groups of five practices and as such may deviate slightly from the original.