Difference between an actual product characteristic and the previously specified or approved characteristic.
Deviation is also often used as a short name for a "Request for Deviation". In this meaning, it is a request by a supplier to her client for authorization to change a product characteristic before the product has been made. The request may be due to the original specified characteristic being unavailable, too costly, or being otherwise less desirable than the requested alternate.
A Request for Deviation should include:
- Detailed description of the deviation sought
- Explanation of why the deviation is sought
- Description of the contractual and practical consequences of not granting the deviation
See also Wes Bucey's "School on Deviations"