Fig. 2. (  A ) Two-sample quantile plots for outpatient surgery patients showing only percentiles. The plot on the  left shows the number of months between the first appointment with the surgeon and surgery. The plot on the  right shows the number of times the patient completed an appointment with the surgeon in clinic during the 24 months preceding surgery. The percentiles were calculated using the Cleveland method. Because of extensive overlap among points, not all 99 points are visible. The 25th, 50th, and 75th percentiles are shown with  × . For the values shown on the  horizontal axis , all cases had equal weights. For the values on the  vertical axis , each case was weighted by its American Society of Anesthesiologists’ Relative Value Guide (ASA RVG) units. The cumulative probability distributions are indistinguishable (months  P = 0.53, visits  P = 0.98). (  B ) Two sample quantile plot for total hospital charges, limited to the 12th to 81st percentiles. The 35th percentile of charges based on ASA RVG units corresponds to the median (50th percentile) of charges based on cases. The 25th, 50th, and 75th percentiles are shown with  × . Fig. 2  B is a positive control showing the large differences in ASA RVG units and cases for financial criteria .