In the software development process, a reference implementation (or, less frequently, sample implementation or model implementation) is the standard from which all other implementations and corresponding customizations are derived. An improvement to a reference implementation reflects an unchanging specification. Conversely, a failed attempt at an implementation may prove that the specification is not suitable and needs improvement itself. Testing the implementation-vs.-specification relationship further enhances the production's inter-process efficiencies:


A reference implementation may or may not be production quality. For example, the Fraunhofer reference implementation of the MP3 standard usually does not compare favorably to other common implementations, such as LAME, in listening tests that determine sound quality.