D. Verification of the declared information
2.18. Role of customs in verification of the declared information. The RKC recognizes the rights of the national customs administrations to ensure the accuracy of the information contained in the declarations by various means, including examination of the goods and any reference documents.
2.19. Examination of goods. The detailed examination of goods is considered a prerogative of any country. The Convention recommends that “(a)ll goods, including means of transport, which enter or leave the Customs territory, regardless of whether they are liable to duties and taxes, shall be subject to Customs control”. Further, “in the application of Customs control, the Customs shall use risk management” and “the Customs shall use risk analysis to determine which persons and which goods, including means of transport, should be examined and the extent of the examination”., Risk assessment allows physical inspections to be significantly limited; in some countries, information about inspections is flagged in the data, while in other countries, no such information is available. It is a good practice for compilers of international merchandise trade statistics to cooperate with customs in reviewing the scope and organization of physical inspection procedures so as to ensure that statistical concerns relating to data quality, verification and validation are fully taken into account. For further information on quality assurance, see chapter IX.
2.20. Reference documents accompanying customs declarations. The RKC acknowledges the need for the customs to use reference documents to support or verify statements made in the declarations in order “to permit control of the operation and to ensure that all requirements relating to the application of Customs law have been complied with”.  The most typical examples of such documents are import licences, documentary evidence of origin, health or phytopathological certificates, commercial invoices, and transport documents. It is advised that compilers make standing arrangements with the customs authorities to secure access, as permitted by law, to whichever of those documents are collected, and to use them as additional sources of information. It is recognized, however, that the use of such documents might be limited only to special cases justified by their economic or other significance.
 See the RKC, General Annex, Chapter 6, Standard 6.1.
 Ibid., Standard 6.3
 Ibid., Standard 6.4
 See also General Annex, Chapter 3, Standard 3.33. Further, the compiler should be aware of special procedures for authorized persons: “For authorized persons who meet criteria specified by the Customs, including having an appropriate record of compliance with Customs requirements and a satisfactory system for managing their commercial records, the Customs shall provide for allowing a single Goods declaration for all imports or exports in a given period where goods are imported or exported frequently by the same person” and “use of the authorized persons’ commercial records to self-assess their duty and tax liability and, where appropriate, to ensure compliance with other Customs requirements” (see RKC, General Annex, Chapter 3, Transitional Standard 3.32.
 . See RKC, General Annex, Chapter 3, Standard 3.16.