Reasonable and Other Doubts: The Problem of Jury Instructions

79 Pages Posted: 29 Jan 2011

See all articles by Robert C. Power

Robert C. Power

Widener University - Commonwealth Law School

Date Written: 1999


This article explores jury instructions and instruction practices concerning reasonable doubt. It establishes that without accurate and understandable jury instructions, the constitutional rights both to a jury trial and to the reasonable doubt standard are ineffective. The article addresses psychological and social science literature on how lay juries are able to understand and to apply the reasonable doubt standard. The article examines the history of such instructions in federal and state courts, noting that the meaning of some phrases common in pattern instructions, such as "moral certainty," have changed over time. It also notes that slight and often unintended variations in boilerplate statements, such as the one-word shift from "fail to act" to "hesitate to act," can make instructions inconsistent to the point of making one clearly pro-prosecution and the other clearly pro-defense. The article examines a modern alternative suggested by the Federal Judicial Center, which attempts to use contemporary language to convey the meaning of reasonable doubt set forth in a series of appellate decisions. It also examines the options numerous courts use of refusing to explain reasonable doubt to juries or explaining it in multiple, inconsistent, ways. The article also suggests some ameliorative techniques, such as use of algorithmic structures, reliance on communication theory, and revisiting some largely discredited instructions to locate phases that can be used to communicate the concept to juries. The article concludes by attempting to formulate a simple and accurate core instruction on reasonable doubt (but doubts that its version is that much better than the others).

Keywords: trial by jury, jury instructions, reasonable doubt, presumption of innocence, due process, moral certainty, analogy instructions, substantial doubt, firmly convinced, real possibility, black box, jury nullification, jury selection, written instructions

JEL Classification: K1, K4

Suggested Citation

Power, Robert C., Reasonable and Other Doubts: The Problem of Jury Instructions (1999). Tennessee Law Review, Vol. 67, p. 45, 1999. Available at SSRN: or

Robert C. Power (Contact Author)

Widener University - Commonwealth Law School ( email )

3800 Vartan Way
Harrisburg, PA 17110-9380
United States
717.541.3980 (Phone)

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