How many units must be reviewed as part of a CIA billing review?
Answer 9: There is no set number of units that the reviewer is required to examine. The sample size is based on the mean and standard deviation of the overpayment amount as calculated in the probe sample. The sample size will vary according to the variability of the probe sample and the size of the population. The units are evaluated to determine the dollar difference between the amount that was reimbursed and the amount that should have been reimbursed. Once these figures are obtained, the mean and standard deviation of the overpayment amount should be calculated. (See response to Question 14 for specific instructions on using the Variable Appraisals feature). This information, in addition to the population size is then entered into the RAT-STATS “Sample Size Estimator” located within the Utility file component. (See response to Question 15 for specific instructions on determining the sample size). Please note, any underpayments identified as part of the review should be considered a
