ISO 9000 does not guarantee product or service quality, but it is a quality system standard. An ISO certified entity is credited for its procedures, not its products. As such, a contractor's product is not guaranteed. However, if a company is ISO certified, owners can be assured the company maintains a quality focus to ensure its products or services are the best that can be provided to consumers. There are different types of ISO quality standards.
Secondary standards provide guidance for the selection and application of primary standards.
Support standards provide quality technology and support in the development and implementation of a quality system. ISO 9000 requires that documentation be made of procedures for performing work that affects the product or service quality. It also requires the work be performed in accordance with the documentation. In addition, records of activities should be retained as evidence of compliance and to compare actual results with what was planned. Lastly, a program should be in place to improve any inefficiencies identified.