Attestation of conformity procedures regulate which tasks will be assumed by the manufacturer and which by the certifying body. Following a decision met by the European Commission, these procedures are laid down in harmonized standards or in European Technical Approvals (ETA).

The Construction Products Directive provides for 6 different attestation of conformity systems. Whereas conformity assessment systems 1, 1+, 2 and 2+ absolutely require notified certification bodies to be involved in the attestation of conformity of products and factory production control, systems 3 and 4 exclusively call on the manufacturer himself to independently assess his conformity.