Multipractice studies: significance of the information given to participating doctors

A total of 1,176 general practitioners were asked to take part in a multipractice study. One group of 568 practitioners was given very detailed information about the study and 19.7 per cent agreed to take part. The remaining 605 practitioners were given only a brief introduction to the study. Of this group 33.4 per cent agreed to take part. Two thirds of the doctors participating in the trial were sent weekly reminders about the study while the remaining third were not. We found that the reminders did not affect the number of patients registered by the practitioners.