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We read the comments of Singh et al with interest. As we mentioned in our response to the letter from Drs Yashimski and Poulose, we did perform an a priori power sample size calculation in the approved protocol design of the study. Although we had proposed 4 individual primary end points for the study, we chose length of stay as the end point upon which to calculate sample size. Our calculations estimated that we would need a sample of 100 patients per group. We decided to close the study, however, following 6 years of randomization. There is indeed a possibility of a type II error as mentioned in our response to the letter of Drs Yashimski and Poulose.
Rogers SJ, Cello JP. ERCP or Laparoscopic Exploration for the Treatment of Suspected Choledocholithiasis?—Reply. Arch Surg. 2010;145(8):796. doi:10.1001/archsurg.2010.129