Effective Jan. 2, 2019, the Centers for Medicare & Medicaid Services (CMS) radically changed its guidance on the use of extrapolation in audits by Recovery Audit Contractors (RACs), Medicare Administrative Contractors (MACs), Unified Program Integrity Contractors (UPICs), and the Supplemental Medical Review Contractor (SMRC).

Extrapolation is a veritable tsunami in Medicare/Medicaid audits. The auditor collects a small sample of claims to review for compliance, then determines the “error rate” of the sample. For example, if 500 claims are reviewed and one is found to be noncompliant for a total of $100, then the error rate is set at 20 percent. That error rate is applied to the universe, which is generally a three-year time period. It is assumed that the random sample is indicative of all your billings, regardless of whether you changed your billing system during that time period or maybe hired a different biller. In order to extrapolate an error rate, contractors must use a “statistically valid random sample” and then apply that error rate on a broader universe of claims, using “statistically valid methods.”

With extrapolated results, auditors allege millions of dollars of overpayments against healthcare providers – sometimes a sum of more than the provider even made during the relevant time period. It is an overwhelming impact that can put a provider and its company out of business.

Prior to this recent change to extrapolation procedure, the Program Integrity Manual (PIM) offered little guidance regarding the proper method for extrapolation.

Prior to 2019, CMS offered broad strokes with few details. Its guidance was limited to generally identifying the steps contractors should take: “a) selecting the provider or supplier; b) selecting the period to be reviewed; c) defining the universe, the sampling unit, and the sampling frame; d) designing the sampling plan and selecting the sample; e) reviewing each of the sampling units and determining if there was an overpayment or an underpayment; and, as applicable, f) estimating the overpayment.”

Well, Change Request 10067 overhauled extrapolation in a huge way.

The first modification to the extrapolation rules is that the PIM now dictates when extrapolation should be used.

Under the new guidance, a contractor “shall use statistical sampling when it has been determined that a sustained or high level of payment error exists. The use of statistical sampling may be used after a documented educational intervention has failed to correct the payment error.” This guidance now creates a three-tier structure:

1. Extrapolation shall be used when a sustained or high level of payment error exists.
2. Extrapolation may be used after documented educational intervention (such as in the Targeted Probe-and-Educate (TPE) program).
3. It follows that extrapolation should not be used if there is not a sustained or high level of payment error or evidence that documented educational intervention has failed.

“High level of payment error” is defined as 50 percent or greater. The PIM also states that the contractor may review the provider’s past noncompliance for the same or similar billing issues or a historical pattern of noncompliant billing practice. This is critical because so many times providers simply pay the alleged overpayment amount if the amount is low or moderate in order to avoid costly litigation. Now, those past times that you simply paid the alleged amounts will be held against you.

Another monumental modification to RAC audits is that the RAC auditor now must receive authorization from CMS to go forward in recovering from the provider if the alleged overpayment exceeds $500,000 or is an amount that is greater than 25 percent of the provider’s Medicare revenue received within the previous 12 months.

The identification of the claims universe was also redefined. Even CMS admitted in the change request that, on occasion, “the universe may include items that are not utilized in the construction of the sample frame. This can happen for a number of reasons, including, but not limited to: a) some claims/claim lines are discovered to have been subject to a prior review; b) the definitions of the sample unit necessitate eliminating some claims/claim lines; or c) some claims/claim lines are attributed to sample units for which there was no payment.”

How many of you have been involved in an alleged overpayment in which the auditor misplaced or lost documents? I know I have. The new rule also states that the auditors must be able to recreate the sample and maintain all documentation pertinent to the calculation of an alleged overpayment.

High-volume providers should face a lower risk of extrapolation if their audited error rate is less than 50 percent and they do not have a history of noncompliance for the same or similar billing issues, or a historical pattern of noncompliant billing practice.