Quantity surveyors work for private and commercial clients, main contractors and subcontractors in the construction industry. Their function is management of the commercial interfaces of construction: writing, negotiating, awarding and administering contracts, including variations and claims arising during the performance of a contract; cost control and cost engineering, i.e. to document and estimate costs, progress, and risks. In the UK, not all quantity surveyors are necessarily chartered surveyors; some may be chartered through the Chartered Institute of Building ("CIOB"). Albeit, the title of 'Chartered Quantity Surveyor' can only be used by Members of the Royal Institution of Chartered Surveyors.