|| Checking for direct PDF access through Ovid
The rate at which primary physicians refer patients to consultants varies considerably, not only within different regions, but also among practices within defined areas. Differences also have been identified between doctors within the same practice. This variation in referral rates is a source of concern because of the costs generated and implications for quality and quantity of care. Many studies that tried to identify the sources for this variation explained only part of it; however, these studies were based on small numbers.