From United States v. Hemphill, 514 F.3d 1350, 1358-59 (D.C. Cir. 2008):

Next, Hemphill's challenge to the government's summary evidence is groundless. ***

Rule 1006 of the Federal Rules of Evidence allows a party to introduce a chart summarizing "[t]he contents of voluminous writings . . . which cannot conveniently be examined in court." To be admissible, a chart must summarize documents so voluminous "as to make comprehension 'difficult and . . . inconvenient,'" although not necessarily "literally impossible"; the documents themselves must be admissible, although the offering party need not actually enter them; the party introducing the chart must make the underlying documents reasonably available for inspection and copying; and the chart must be "accurate and nonprejudicial." United States v. Bray, 139 F.3d 1104, 1109-10 (6th Cir. 1998). In addition, as part of the foundation for a chart, the witness who prepared the chart should introduce it. Id. at 1110.

Hemphill contests the admissibility of the government's charts on all four of these conditions, but we address only one of her arguments in detail. The rest turn on her misapprehension that the government must actually introduce the documents on which it bases a summary chart. To the contrary, the point of Rule 1006 is to avoid introducing all the documents. As long as a party has laid a foundation for the underlying documents, a chart summarizing them can itself be evidence under Rule 1006. Here, the government proffered certifications for the documents under Rule 902(11), and Hemphill's counsel does not appear to have objected.

In her most serious contention, Hemphill claims the charts were argumentative, prejudicial, and selective. In particular, she says Novak, the government auditor, used his accounting skills to prepare charts purposefully to show that Hemphill had a source of funds outside her regular income. But the fact that a non-expert witness, like Novak, prepared a chart or testified about it does not make the chart inadmissible. See United States v. Scales, 594 F.2d 558, 563 (6th Cir. 1979) (necessary only that the investigator "had properly catalogued the exhibits . . . and had knowledge of the analysis"). Nor is it problematic for a witness to perform some calculations in preparing a chart. United States v. Evans, 910 F.2d 790, 799-800 (11th Cir. 1990) (government witness added $ 100 per month to the defendant's accounts); United States v. Jennings, 724 F.2d 436, 442 (5th Cir. 1984) (government exhibit extrapolated defendant's reimbursement by assuming a value for average daily expenditure). Even if the calculations are mistaken, the chart is itself admissible, since admissible evidence may be unpersuasive and a defendant has the opportunity to rebut it. Evans, 910 F.2d at 800.