firsttoinvent

First-to-invent is a priority principle in United States patent law under which the patent for an invention could be granted to the inventor who first conceived the invention and diligently reduced it to practice, even if another person filed a patent application later. This approach emphasizes the inventor’s actual timeline of conception and development rather than the filing date of the patent application.

Historically, the United States operated under a first-to-invent system for many decades. Priority disputes were resolved through interference proceedings in which evidence of conception, reduction to practice, and diligence were weighed to determine who was the true inventor. The standard involved proving the timeline of ideas and work, not merely who filed first.

The regulatory landscape changed with the America Invents Act (AIA) of 2011, which transitioned the United States to a first-to-file system for most patent applications. The shift took effect in March 2013, aligning U.S. practice with the majority of other countries. Under the post-AIA regime, filing date generally determines priority, though derivation proceedings exist to address situations where an inventor may have derived the invention from another inventor inappropriately. Interference provisions from the pre-AIA era were replaced by these derivation procedures for later filings and related challenges.

Implications of the change include a greater emphasis on timely filing and on strategic disclosure, as the earliest inventor’s concept may be overshadowed by the first filer. Proponents argue that first-to-file reduces litigation over invention dates and simplifies patent prosecution, while critics contend it can disadvantage inventors with fewer resources or slower development cycles.

See also: patent law, America Invents Act, interference, derivation, conception, reduction to practice.