Section 404.1645 - How and when we determine whether the performance accuracy standard is met(a)How we determine performance accuracy. We determine a State agency's performance accuracy rate on the basis of decision and documentation errors identified in our review of the sample cases.(b)Frequency of review. Title II and title XVI initial performance accuracy are monitored together on a quarterly basis. The determinations as to whether the performance accuracy threshold has been met is made at the end of each quarter each year. Quarterly State-by-State combined initial performance accuracy rates are compared to the established threshold level.