CMS Pub. 100-08, ch. 8, § 8.4.3.1

Following selection of the provider or supplier, the contractor in conjunction with a

statistical expert shall determine the time period and the number of days, weeks, months,

or years for which sampling units will be reviewed. For RACs and SMRC, CMS will

approve the time period. The target universe shall be selected based on these criteria.

The scope of the review is determined by considering several factors that include, but are

not limited to:

• How long the pattern of sustained or high level of payment error is believed to

have existed,

• The volume of claims that are involved,

• The length of time that a national coverage decision or local coverage

determination has been in effect,

• The extent of prepayment review already conducted or currently being

conducted,

• The dollar value of the claims that are involved relative to the cost of the

sample,

• The applicable time periods for reopening claims (see Pub. 100-04, chapter 34,

section 10.6),

• A clear specification of the specific data elements to be used for defining the

date (type of date, e.g., day, month, year).

As examples: If dates of service are used, specify, as needed, whether the dates

are line service dates or claim service dates, the first day of the billing statement

or the ending date of service, etc. If a span of dates is used, clarify the criteria

used when the span overlaps the boundary of one of the other criterion date

ranges. If paid dates or receipt dates are used, clarify the role of the adjusted

claims.

All case documentation, including the overpayment demand letter and

methodology, should consistently reflect the same date range and specify the

same type of date.

NOTE: When sampling claims that are paid through cost report (as opposed to claims

paid under a PPS reimbursement methodology), all claims reviewed must be

drawn from within a provider’s/supplier’s defined cost reporting year. If the

period under review is greater than one year, it is important to select a

separate sample for each cost-reporting year.