Post clearance audit (PCA) or audit-based controls are defined by the Revised Kyoto Convention as measures by which the Customs satisfy themselves as to the accuracy and authenticity of declarations through the examination of the relevant books, records, business systems and commercial data held by persons concerned. Post-clearance audit is a critical control methodology for Customs and other border regulatory authorities as it enables them to apply a multi-layered risk-based control approach by moving from a strictly transaction-based control environment to a stronger audit-based administration.