“…Independent Variables (Anesthesiologist and Patient interactions, Age, Gender, Academic vs. Nonacademic, Case Complexity, Rural vs. Urban) We obtained billing data for all physician-patient interactions performed by specialist anesthesiologists from British Columbia, (BC: BC Medical Services Commission), Quebec (QC: Regie de l'Assurance Maladie du Quebec), and Ontario (ON: Ministry of Health and Long Term Care) for the 10-yr period from Jan. 1,1993 to Dec. 31, 2002. The information included the age of the anesthesiologist at the time of billing (divided into age groups of less than 51, 51-64, 65 and older), billing code for the act, unique anonymized patient identifier code, and the date of the procedure.…”