Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This paper investigates the surgical volume–outcome relationship for patients undergoing hip fracture surgery in Quebec between 1991 and 1993. Using a duration model with multiple destinations which accounts for observed and unobserved (by the researcher) patient characteristics, our initial estimates show that higher surgical volume is associated with a higher conditional probability of live discharge from the hospital. However, these results reflect differences between hospitals rather than differences within hospitals over time: when we also control for differences between hospitals that are fixed over time, hospitals performing more surgeries in period t + 1 than in period t experience no significant change in outcomes, as would be predicted by the ‘practice makes perfect’ hypothesis. The volume–outcome relationship for hip fracture patients thus appears to reflect quality differences between high and low volume hospitals. © 1997 John Wiley & Sons, Ltd.