date of invention
The earliest of the following dates:
(a) the date the inventor filed either a provisional or non-provisional ("full") application; or
(b) the date the inventor can prove he or she built and tested the invention in a NAFTA or WTO country; or
(c) the date the inventor can prove he or she conceived of the invention in a NAFTA or WTO country and diligently reduced it to practice.Date of invention, while important, will no longer be the determinant of who receives a patent, once the "First-Inventor-to-File" provision of the America Invents Act takes effect. Once that provision is implemented, the filing date will control who gets a patent.