What is the difference between derivation and priority of invention?
Derivation and priority of invention both focus on inventorship. Derivation addresses originality, i.e., who invented the subject matter, whereas priority focuses on which party invented the subject matter first.
The answer to this question can be found in chapter 2100 of the MPEP. This chapter covers patentability.
The answer is from the 9th Edition, Revision 08.2017. Depending on future changes to the MPEP, the question and answer may or may not be applicable in later Editions or revisions.
This question and answer comes from section 2137 of the MPEP. The following is a brief summary of section 2137.
2137 Pre-AIA 35 U.S.C. 102(f)
This section discusses pre-AIA 35 U.S.C. 102(f) which states that a person shall be entitled to a patent unless he did not himself invent the subject matter sought to be patented. A rejection under 35 U.S.C. 102(f) is proper where it can be shown that an applicant derived an invention from another. Derivation requires complete conception by another and communication to the alleged deriver. The party alleging derivation does not have to prove an actual reduction to practice, derivation of public knowledge, or derivation in this country. In addition, there is a discussion that pre-AIA 35 U.S.C. 102(f) may apply where pre-AIA 35 U.S.C. 102(a) and pre-AIA 35 U.S.C. 102(e) are not available statutory grounds for rejection.