; and (2) background checks and vetting. (b) Revalidation The Commissioner of U.S. Customs and Border Protection shall implement a revalidation process for all Tier 2 and Tier 3 C–TPAT program participants. Such process shall require— (1) a framework based upon objective, risk based criteria for identifying participants for periodic revalidation at least once every four years following the initial validation of such participants; (2) on-site assessments at appropriate foreign and domestic locations utilized by such a participant in its international supply chain; and (3) an annual plan for revalidation that includes— (A) performance measures; (B) an assessment of the personnel needed to perform such revalidations