In examining applications subject to pre-AIA 35 U.S.C. 102, the effective filing date of the claimed invention is the actual filing date of the U.S. application, unless situation (A), (B), or (C) as set forth below applies. Note that the actual U.S. filing date of an application that entered the national stage under 35 U.S.C. 371 is the international filing date. See 35 U.S.C. 363 and MPEP § 1893.03(b).

1. (A) If the application is a continuation or divisional of one or more earlier U.S. applications or international applications and if the requirements of 35 U.S.C. 120 or 365(c) have been satisfied, the effective filing date of the claimed invention is the same as the earliest filing date in the line of continuation or divisional applications.
2. (B) If the application is a continuation-in-part of an earlier U.S. application or international application, any claims in the new application not supported by the specification and claims of the parent application have an effective filing date equal to the actual filing date of the new application. Any claims which are fully supported under 35 U.S.C. 112 by the earlier parent application have the effective filing date of that earlier parent application.
3. (C) If the application properly claims benefit under 35 U.S.C. 119(e) to a provisional application, the effective filing date of the claimed invention is the filing date of the provisional application for any claims which are fully supported under the first paragraph of 35 U.S.C. 112 by the provisional application.

The effective filing date for claims subject to pre-AIA 35 U.S.C. 102 is not the filing date of the foreign priority document, although the filing date of the foreign priority document may be used to overcome certain references. See MPEP § 2136.05 et seq.

See MPEP § 1893.03(c), subsection III for benefit claims under 35 U.S.C. 119(e), 120, or 365(c) in an application that entered the national stage under 35 U.S.C. 371. See MPEP §§ 211.01(c) and 1895 for additional information on determining the effective filing dates of claimed inventions in a continuation, divisional, or continuation-in-part of a PCT application designating the U.S. See also MPEP §§ 1895.01 and 1896 which discuss differences between applications filed under 35 U.S.C. 111(a) and international applications that enter national stage under 35 U.S.C. 371.