Fig. 1. Adjusted operating room (OR) utilizations obtained with 3 months of historical data. The average adjusted OR utilization is the independent variable in the computer simulations. The dashed line is the line of equality between average adjusted OR utilizations and measured adjusted OR utilizations. The pair of lines labeled with “90%” give 90% CIs for average adjusted OR utilizations obtained by using 3 months of data. The next pair of lines labeled “95%” give the corresponding 95% CIs. For example, if a hypothetical surgeon's measured adjusted utilization is 80% during a 3-month period, then the 95% CI for the average adjusted utilization ranges from 53% to 88%. In more “real world” conditions (e.g. , surgeon takes vacation or cases are cancelled), the CIs would be wider.