CMS Pub. 100-08, ch. 8, § 8.4.1.5

The sampling methodology used in estimations of overpayments must be reviewed and

approved by a statistician or by a person with equivalent expertise in probability

sampling and estimation methods. This is done to ensure that a statistically appropriate

sample is drawn, and that appropriate methods for estimating the overpayments are

followed. The contractor shall obtain from the statistical expert a written approval of the

methodology for the type of statistical sampling to be performed. Regardless of whether

this sampling methodology is applied routinely and repeatedly, each time a sample size

calculation or estimation is performed, a detailed methodology (See Section 8.4.7.1.)

should be submitted by the statistical expert to the corresponding contractor.

Prior to releasing a findings letter or overpayment demand letter, the contractor shall have

the statistical expert review the results of the sampling and any other subsequent

overpayment estimation or extrapolation. The contractor shall verify that the statistical

findings have been reviewed and agreed to by the contractor.

If questions or issues arise, the contractor shall also involve the statistical expert.

At a minimum, the statistical expert (either on-staff or consultant) shall meet one of the

following criteria:

• Have significant coursework in probability and estimation methodologies, and at

least 10 years of experience applying methods of statistical sampling and

interpreting the results.

• Possesses a Bachelor’s degree (e.g., B.A., B.S.) in statistics or in some related

field (e.g., psychometrics, biostatistics, econometrics, mathematics) with

significant coursework in probability and estimation methodologies, and at least 6

years of experience applying methods of statistical sampling and interpreting the

results.

• Possesses a Master’s degree (e.g., M.A., M.S.) in statistics or in some related field

with significant coursework in probability and estimation methodologies, and at

least 4 years of experience applying methods of statistical sampling and

interpreting the results.

• Possess a Doctoral degree in statistics or in some related field with significant

coursework in probability and estimation methodologies, and at least 1 year of

experience applying methods of statistical sampling and interpreting the results.

If the contractor does not have staff with sufficient statistical experience as outlined here,

it shall obtain such expert assistance prior to conducting statistical sampling.