Hindsight Bias and Law

Abstract. Hindsight bias is the tendency to overestimate the foreseeability of an outcome once it is known. This bias has implications for decisions made within the legal system, ranging from judgments made during investigations to those in court proceedings. Legal decision makers should only consider what was known at the time an investigation was conducted or an offense was committed; however, they often review cases with full knowledge of a negative outcome, which can affect their judgments about what was knowable in the past. We conducted a systematic review of the literature on hindsight bias and law. We present five areas of law that hindsight bias affects (medical malpractice, forensic investigation, negligence, patent, criminal), two types of evidence that may lead to hindsight bias (visual and auditory evidence), and hindsight bias in experts and judges. Finally, we discuss strategies for reducing hindsight bias in legal decisions and recommend future research.