Fed.R.Civ.P. 33(d) provides:

Where the answer to an interrogatory may be derived or ascertained from the business records, including electronically stored information, of the party upon whom the interrogatory has been served ... and the burden of deriving ... the answer is substantially the same for the part[ies]..., it is a sufficient answer to such interrogatory to specify the records from which the answer may be derived ... and to afford to the party serving the interrogatory reasonable opportunity to examine ... such records.... A specification shall be in sufficient detail to permit the interrogating party to locate and to identify, as readily as can the party served, the records from which the answer may be ascertained.

The defendants in L.H. v. Schwarzenegger, 2007 U.S. Dist. LEXIS 73752 (E.D. Cal. Sept. 21, 2007), relied on Rule 33(d) (although they neglected to cite it) when they referred to records they had produced to answer interrogatories. But their answers simultaneously called into question the adequacy of the records to furnish a reliable answer. Not allowed. Held:

[A]ny reference[s] to records contained in the interrogatories ... are out of compliance with Rule 33(d) because that rule requires an affirmative, verified representation that the information requested can indeed be found in the documents.... The point of Rule 33(d) is that when reference to specific records is made, the rule requires a verification that the information requested is contained therein, not that it "might be," or "could be." Of course, when such nebulous assurances are made as were made here, when it comes to trial or summary judgment, defendants would object to the foundation of the statistics used by plaintiffs thereby reaping an improper windfall from their improper responses.

Usable quote of note: "[U]nder Rule 33(d), the responding party chooses to produce business records in answer to the interrogatories — not to avoid answering them“ (citation omitted).