[Editor Note: This MPEP section is not applicable to applications subject to the first inventor to file provisions of the AIA unless being relied upon to overcome a rejection under pre-AIA 35 U.S.C. 102(g). See 35 U.S.C. 100 (note) and MPEP § 2159. For a discussion of 37 CFR 1.130, affidavits or declarations of attribution or prior public disclosure in applications subject to the first inventor to file provisions of the AIA, see MPEP § 717. For a discussion of affidavits or declarations under 37 CFR 1.131(c), see MPEP § 718.]
Where conception occurs prior to the date of the reference, but reduction to practice is afterward, it is not enough merely to allege that the inventor or inventors had been diligent. Rather, applicant must show evidence of facts establishing diligence.
In determining the sufficiency of a 37 CFR 1.131(a) affidavit or declaration, diligence need not be considered unless conception of the invention prior to the effective date is clearly established, pursuant to 37 CFR 1.131(b), diligence comes into question only after prior conception is established.
In patent law, an inventor is either diligent at a given time or he is not diligent; there are no degrees of diligence. An applicant may be diligent within the meaning of the patent law when he or she is doing nothing, if his or her lack of activity is excused. Note, however, that the record must set forth an explanation or excuse for the inactivity; the USPTO or courts will not speculate on possible explanations for delay or inactivity. See In re Nelson, 420 F.2d 1079, 164 USPQ 458 (CCPA 1970). Diligence must be judged on the basis of the particular facts in each case. See In re Steed, 802 F.3d 1311, 1320, 116 USPQ2d 1760, 1767 (Fed. Cir. 2015)(“Although the claimed invention is a method conducted by computer software, this does not avoid the need for sufficient evidentiary specificity”). See MPEP § 2138.06 for a detailed discussion of the diligence requirement for proving prior invention.
Under 37 CFR 1.131(a), the critical period in which diligence must be shown begins just prior to the effective date of the reference or activity and ends with the date of a reduction to practice, either actual or constructive (i.e., filing a United States patent application). Note, therefore, that only diligence before reduction to practice is a material consideration. Any lack of due diligence between an actual reduction to practice of an invention and the filing of an application thereon is not relevant to the sufficiency of an affidavit or declaration under 37 CFR 1.131(a).