The Tenth Circuit Makes Pretty Good Sense of the Inference-upon-Inference Rule

Famously -- "famously," in any event, to those of us who are interested in multistage inference -- , famously, Abraham Lincoln called one set of multistage inferences -- those of his debate opponent Stephen Douglas --, Lincoln called Douglas' pyramided inferences "as thin as the homeopathic soup that was made by boiling the shadow of a pigeon that had starved to death." See Passantino v. Board of Education, 52 A.D.2d 935, 383 N.Y.S.2d 639 (1976)(comment made at Lincoln-Douglas debate at Quincy, Illinois, Oct. 13, 1858). As hard as it is to resist such a lovely metaphor or the word of America's most beloved President, most American Evidence scholars have done so in this instance: they have roundly condemned the supposed prohibition against piling an inference upon an inference. Now, however, the 10th Circuit has suggested that the inference-upon-inference rule is not a prohibition but a signpost that should warn courts, particularly in criminal cases, against allowing juries (or, presumably, judges) from reaching factual conclusions that are too weakly supported by evidence. In United States v. Summers, 2005 U.S. App. LEXIS 14823, 9*-11* (July 21, 2005)(footnotes omitted) the 10th Circuit Court of Appeals said:

In the civil context, the import of the "inference upon inference" rule has largely been eroded. See Salter v. Westra, 904 F.2d 1517, 1525 (11th Cir. 1990); Cora Pub, Inc. v. Cont'l Cas. Co., 619 F.2d 482, 485-86 (5th Cir. 1980); see also N.Y. Life Ins. Co. v. McNeely, 52 Ariz. 181, 79 P.2d 948, 955 (Ariz. 1938) (setting forth a construction of the rule that has been adopted in numerous jurisdictions); 1A John Henry Wigmore, Evidence in Trials at Common Law Section 41 (Tillers rev. 1983) (criticizing the rule in both contexts as "fallacious and impracticable"). In criminal cases, however, its common-sense dictate continues to bear currency. While some courts have rejected a mechanistic interpretation of the rule, n3 we find its underpinnings to be sound, arising as they do from the requirement that the government bears the burden to prove its case beyond a reasonable doubt. The government may satisfy this burden, in whole or in part, through the use of circumstantial evidence open to interpretation by the jury. Inferences are necessary and indeed proper in a criminal trial, and "a jury has wide latitude to determine factual issues and to draw reasonable inferences from circumstantial evidence." United States v. McCarrick, 294 F.3d 1286, 1293 (11th Cir. 2002). An inference is reasonable if it "flows from logical and probabilistic reasoning," i.e., with experience serving as the touchstone, a jury's inference is permissible where there is a reasonable probability that the conclusion flows from the facts in evidence. n4 Jones, 44 F.3d at 865. The rule that prohibits the stacking of inference upon inference merely indicates that at some point along a rational continuum, inferences may become so attenuated from underlying evidence as to cast doubt on the trier of fact's ultimate conclusion. In other words, "the chance of error or speculation increases in proportion to the width of the gap between underlying fact and ultimate conclusion where the gap is bridged by a succession of inferences, each based upon the preceding one." United States v. Shahane, 517 F.2d 1173, 1178 (8th Cir. 1975).

While preserving the "inference upon inference" rule in this circuit, we see little tension between our understanding of its import and that espoused in the cases noted above. Nor have our previous cases employed a formalistic approach to the operation of the rule. ...

Like many courts that have addressed the issue, we do not foreclose the possibility that a reasonable inference built on yet another reasonable inference may in some cases sustain a conviction. However, we believe the "inference upon inference" rule serves as an appropriate signpost, cautioning reviewing courts to measure the "gap" between fact and conclusion before acquiescing in the jury's leap.

Although the 10th Circuit didn't get absolutely everything right -- the strength of an inference based on a series of inferences is not as dependent on the number of inferences as the 10th Circuit imagines -- there is much to be said for the approach that the 10th Circuit takes. The 10th Circuit's approach tells judges that when evaluating the strength or sufficiency of evidence (at least in criminal cases) they must decompose the foundation of a final inference into a series of inferences upon which such a final inference rests and judges must then assess the strength or force of the entire chain (I would say "complex") of inferences. There is wisdom -- and valuable inferential discipline -- in this approach; the existence of pyramided inferences is not a myth.