1. (1) To determine an improper payment from a sample, the medicaid agency may extrapolate to the universe from which the sample was drawn:

   1. (a) If the audit identifies a sustained high level of payment error involving the provider; or
   2. (b) When the agency has documented educational intervention to the provider and the education has failed to correct the provider's level of payment error.
2. (2) If during the course of the audit, an entity adjusts or rebills a claim or encounter that is part of the audit sample or universe, the original claim or encounter amount remains in the audit sample or universe.

3. (3) When the agency uses the results of an audit sample to extrapolate the amount to be recovered, the agency provides the entity with the following information:

   1. (a) The sample size.
   2. (b) The method used to select the sample.
   3. (c) The universe from which the sample was drawn.
   4. (d) Any formulas or calculations used to determine the amount of the improper payment.

[Statutory Authority: RCW 41.05.021, 41.05.160, and C.F.R. Sections 438.608 through 438.610. WSR 20-02-100, § 182-502A-0601, filed 12/31/19, effective 1/31/20. Statutory Authority: RCW 41.05.021, 41.05.160, 2017 c 242. WSR 18-07-050, § 182-502A-0601, filed 3/14/18, effective 4/14/18. Statutory Authority: RCW 41.05.021 and 41.05.160. WSR 15-01-129, § 182-502A-0601, filed 12/19/14, effective 1/19/15.]