An ISO standard is a document that provides requirements, specifications, guidelines or characteristics that can be used consistently to ensure that materials, products, processes and services are fit for their purpose. Many staffing firms undergo ISO certification in order to prove the trustworthiness of their processes and systems. The most common standard used by staffing firms is ISO 9001:2000, the world’s most popular standard for quality management. ISO 9001 is now under review and an updated version is due to be available by the end of 2015.