|| Checking for direct PDF access through Ovid
We explored whether a previously successful initiative to improve first-case on-time starts succeeded because (i) preoperative steps started earlier (but the process did not necessarily improve) or (ii) the process was brought into better control.We analysed 35 months of data comprising 28 882 first cases to calculate the difference of the time a patient entered the operating room (OR) vs the scheduled entry time. Median and inter-quartile range were used to evaluate changes in distribution parameters. A statistical process-control methodology was used to compare the differences in performance between the pre- and post-intervention phases.Post-intervention first cases entered the OR on average within 4 min [95% confidence interval (CI): 4–5 min] of the scheduled start time, as opposed to within 8 min (95% CI: 8–8 min) in the pre-intervention period. The median delay decreased from 5 min (95% CI: 5–5 min) to 2 min (95% CI: 2–2 min). The inter-quartile range of the difference between the scheduled start time and the first case in room time decreased from 13 min (95% CI: 13–13 min) to 10 min (95% CI: 9–10 min).The reduction in inter-quartile range demonstrates that improvement in on-time starts resulted from the process being in better control. The start time of preoperative preparatory activities did not move earlier, which means that OR and preoperative staff do not need to arrive at work earlier. Improvements resulting from the process being in control were sustained.