The Evidence of Things Not Seen: Non-Matches as Evidence of Innocence

Abstract:     
Exonerations famously reveal that eyewitness identifications, confessions, and other “direct” evidence can be false, though police and jurors greatly value them. Exonerations also reveal that “circumstantial” non-matches between culprit and defendant can be telling evidence of innocence (e.g., an aspect of an eyewitness’s description of the perpetrator that does not match the suspect she identifies in a lineup, or a loose button found at the crime scene that does not match the suspect’s clothes). Although non-matching clues often are easily explained away, making them seem uninteresting, they frequently turn out to match the real culprit when exonerations reveal that the wrong person was convicted. This Article uses “non-exclusionary non-matches” and what would seem to be their polar opposite, inculpatory DNA, to show that: (1) all evidence of identity derives its power from the aggregation of individually uninteresting matches or non-matches, but (2) our minds and criminal procedures conspire to hide this fact when they contemplate “direct” and some “circumstantial” evidence (e.g., fingerprints), making those forms of evidence seem stronger than they are, while, conversely, (3) our minds and procedures magnify the circumstantial character of non-exclusionary non-matches, making them seem weaker than they are. We propose ways to use circumstantial matches and non-matches more effectively to avoid miscarriages of justice.

Number of Pages in PDF File: 113

Keywords: criminal law, identity, evidence, matches and non-matches, Bayesian inference, heuristic bias

JEL Classification: K4, K14

working papers series