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Introducing a methodology for estimating duration of surgery in health services research


Objectives — The duration of surgery is an indicator for the quality, risks, and efficiency of surgical procedures. We introduce a new methodology for assessing the duration of surgery based on anesthesiology billing records, along with reviewing its fundamental logic and limitations.

Study Design and Setting — The validity of the methodology was assessed through a population-based cohort of patients (n=480,986) undergoing elective operations in 246 Ontario hospitals with 1,084 anesthesiologists between April 1, 1992 and March 31, 2002 (10 years).

Results — The weaknesses of the methodology relate to missing data, self-serving exaggerations by providers, imprecisions from clinical diversity, upper limits due to accounting regulations, fluctuations from updates over the years, national differences in reimbursement schedules, and the general failings of claims base analyses. The strengths of the methodology are in providing data that match clinical experiences, correspond to chart review, are consistent over time, can detect differences where differences would be anticipated, and might have implications for examining patient outcomes after long surgical times.

Conclusions — We suggest that an understanding and application of large studies of surgical duration may help scientists explore selected questions concerning postoperative complications.



Redelmeier DA, Thiruchelvam D, Daneman N. J Clin Epidemiol. 2008; 61(9):882-9. Epub 2008 May 12.

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