(a) Case Reviews and Sampling - In preparing the error reports required by this subpart, States, the District of Columbia and Puerto Rico shall conduct comprehensive reviews of case records using a methodology established by the Secretary. For purposes of the case reviews, States, the District of Columbia and Puerto Rico shall select a random sample of case records which is estimated to achieve the calculation of an estimated annual amount of improper payments with a 90 percent confidence interval of ±5.0 percent.

(b) Methodology and Forms - States, the District of Columbia and Puerto Rico must prepare and submit forms issued by the Secretary, following the accompanying instructions setting forth the methodology to be used in conducting case reviews and calculating the error rates.

(c) Reporting Frequency and Cycle - States, the District of Columbia and Puerto Rico shall conduct case reviews and submit error rate reports to the Department according to a staggered three-year cycle established by the Secretary such that each State, the District of Columbia, and Puerto Rico will be selected once, and only once, in every three years.

(d) Access to Federal Staff - States, the District of Columbia and Puerto Rico must provide access to Federal staff to participate and provide oversight in case reviews and error rate calculations, including access to forms related to determining error rates.

(e) Record Retention - Records pertinent to the case reviews and submission of error rate reports shall be retained for a period of five years from the date of submission of the applicable error rate report or, if the error rate report was revised, from the date of submission of the revision. Records must be made available to Federal staff upon request.