Verification and validation (also abbreviated as V&V) are independent procedures that are used together for checking that a product, service, or system meets requirements and specifications and that it fulfills its intended purpose. These are critical components of a quality management system such as ISO 9000. The words "verification" and "validation" are sometimes preceded with "independent", indicating that the verification and validation is to be performed by a disinterested third party. "Independent verification and validation" can be abbreviated as "IV&V".
In reality, as quality management terms, the definitions of verification and validation can be inconsistent. Sometimes they are even used interchangeably.
However, the PMBOK guide, a standard adopted by the Institute of Electrical and Electronics Engineers (IEEE), defines them as follows in its 4th edition:
Similarly, for a Medical device, the FDA (21 CFR) defines Validation and Verification as procedures that ensures that the device fulfil their intended purpose.
ISO 9001:2015 (Quality management systems requirements) makes the following distinction between the two activities, when describing design and development controls:
It also notes that verification and validation have distinct purposes but can be conducted separately or in any combination, as is suitable for the products and services of the organization.