The “effective filing date” for a claimed invention in a patent or application for patent is the earlier of: (1) the actual filing date of the patent or the application containing a claim to the invention; or (2) the filing date of the earliest priority application (i.e., the earliest filed provisional, nonprovisional, international, or foreign application) to which a patent or patent application is entitled to a right of priority for the claimed invention. See 35 U.S.C. § 100(i). Effective filing date is evaluated on a claim-by-claim basis. In general, this means a claim is entitled to the filing date of the earliest filed application supporting that claim.
The effective filing date determines the universe of prior art available against a claim or application, and also determines whether an application will be examined under the pre-AIA first-to-invent system, or AIA’s first-inventor-to-file system. The following figure depicts the impact of the effective filing date on choice of law:
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If the effective filing date of all claims that a patent or application contains (or contained at any time) is after March 15, 2013, then the prior art provisions, exceptions, and definitions of AIA apply to all claims. Conversely, if all claims that a patent or application contains have an effective filing date before March 16, 2013, only the pre-AIA prior art provisions apply. If, however, an application contains (or contained at any time) at least one claim having an effective filing date before March 16, 2013, and at least one claim having an effective filing date after March 15, 2013, all of the claims of that application are subject to the prior art provisions of AIA §§ 102 and 103 plus pre-AIA §§ 102(g). See 125 Stat. 293.