The International Valuation Standards Council (IVSC) is an independent, not-for-profit organisation that acts as the global standard setter for valuation practice and the valuation profession.
You can access the International Valuation Standards here.
"Standards are published documents setting out specifications and procedures designed to ensure products, services and systems are safe, reliable and consistently perform the way they were intended to. They establish a common language which defines quality and safety criteria." (Standards Australia).
Standards are developed by various bodies, agencies, trade, and professional associations. Some standards are voluntary. Others are enforced by legislation and are mandatory.