A common deficiency highlighted in recent PTAB decisions denying institution of an IPR petition is that an expert declaration offers only “conclusory” statements in relation to one or more key aspects of the alleged ground of unpatentability. For example, in a decision denying institution in IPR2016-00011, the PTAB commented that “Dr. Harrigan’s opinion in this respect is conclusory and, therefore, unpersuasive. See Verlander v. Garner, 348 F.3d 1335, 1371 (Fed. Cir. 2003) (Board has discretion to accord little weight to broad conclusory statements from expert witness).” Under the existing rules, an expert’s conclusory statement may be fatal to institution as shown in the preceding case. When the new rules go into effect on May 2nd (see “USPTO Releases New Rules For AIA Post-Grant Proceedings”), allowing patent owners for the first time to include expert declarations in their preliminary responses in rebuttal to a petitioner’s expert, the question of whether a statement in an expert declaration is merely “conclusory” or fully supported by evidence will be drawn into sharper relief.