General Purpose

8.4.1.1 – General Purpose (Rev. 906, Issued: 09-26-19; Effective: 01-02-19; Implementation: 01-02-19) The purpose of this section is to provide instructions for contractors on the use of statistical sampling in their reviews and estimation of overpayments to be recovered by recoupment, offset, or otherwise. The intent of these instructions is to ensure that a probability sample drawn from the sampling frame of the target population yields a valid estimate of an overpayment in the target population. This means that every element in the sampling frame has a non-zero probability of being selected. It is important to note that this is consistent with methodologies such as stratification and cluster sampling as needed to warrant statistically sound inferences from the sample. Reviews conducted by the contractors to assist law enforcement with the identification, case development, and/or investigation of suspected fraud or other unlawful activities may use sampling methodologies that differ from those prescribed herein. However, in those cases, the methodologies used shall be well-accepted methodologies amongst statisticians, and complete explanation shall be provided for why the methodology used was the appropriate methodology in the situation. These instructions are provided so that a sufficient process is followed when conducting statistical sampling to project overpayments. Failure by a contractor to follow one or more of the requirements contained herein does not necessarily affect the validity of the statistical sampling that was conducted or the projection of the overpayment. An appeal challenging the validity of the sampling methodology must be predicated on the actual statistical validity of the sample as drawn and conducted and must demonstrate actual error in the methodology that affects the overpayment amount. Failure by the contractor to follow one or more of the requirements contained herein may result in review by CMS of their performance, but should not be construed as necessarily affecting the validity of the statistical sampling and/or the projection of the overpayment.