studies have found that jurors typically understand a
little more than half the instructions they are presented
with and that in some cases there is no difference in
comprehension rates between participants who receive
pattern instructions and those not instructed at all. Some
studies have found comprehension rates below 40%,
and some have found comprehension rates in the 70% to
80% range. This variability may be due in part to the
measure used to assess comprehension, with higher
rates obtained when True/False or other multiple-choice
recognition questions are used and lower rates when
participants are asked to paraphrase instructions.
Comprehension problems exist for both substan-
tive and procedural instructions. In terms of substan-
tive law, a variety of criminal instructions have been
shown to be problematic, including those on murder,
assault, robbery, theft, and insanity. For example,
research has shown that about one third of jurors are
unable to articulate that intent is an essential part of
first-degree murder. In addition, other research has
shown that jurors are not sensitive to the subtle, but
important, differences between different insanity stan-
dards (i.e., the M’Naghten Standard, the American
Law Institute standard, and the Guilty but Mentally Ill
standard). Instead, jurors tend to use their own beliefs
about insanity in their decision making.
Death penalty instructions appear to be particularly
problematic to jurors. In death penalty cases, jurors
are typically asked to weigh aggravating factors (spe-
cific aspects of the crime that must be present to sen-
tence a defendant to death) against any mitigating
factors (aspects of the crime or the defendant’s life
that make life imprisonment an appropriate verdict).
Although the concept of aggravation appears to be
reasonably well understood by jurors, mitigation (a
critical safeguard that prevents the defendant from
being unjustly executed) is not. Jurors sometimes con-
fuse the factors as well (i.e., erroneously believe a
mitigating factor to be an aggravating factor).
Research has indicated that jurors have consider-
able difficulty in comprehending a variety of concepts
from civil trials, such as negligence and liability, and
have difficulty in determining appropriate damage
awards as a result. Some problems associated with
civil instructions are likely a result of the complexity
of civil law. Difficulties with civil instructions may
also occur because jurors are less familiar with civil
legal standards than criminal law concepts (as civil
issues are portrayed less frequently in news reports
and fictional legal stories presented on television, infilms, and in books). In addition, in the United States,
civil jurors are typically given minimal guidance as to
how abstract concepts such as pain and suffering
should be transformed into specific monetary amounts
for damages.
Procedural instructions are also problematic for
jurors. Some research has shown that jurors do not fully
comprehend the meaning of presumption of innocence
and burden of proof in criminal cases. There is confu-
sion in the minds of jurors as to whether the burden of
proof rests entirely on the prosecution and the defen-
dant does not have to present any evidence.
In addition, jurors do not appear to have a complete
understanding of the different “standards of proof.”
The standard of proof is the level of certainty neces-
sary for a fact finder (i.e., the jury) to find that charges
against a defendant in a criminal case or the claims
against a defendant/respondent in a civil case are true.
In the United States, “beyond a reasonable doubt” is
the standard used in criminal trials. Individuals in the
legal community have estimated this standard to mean
requiring approximately a 90% certainty of guilt. It is
the highest standard of proof required, reflecting the
belief that it is far worse to convict an innocent person
than to acquit a guilty one, yet absolute certainty need
not be achieved for a conviction. “Preponderance of
evidence” is the standard of proof used in most civil
cases and requires that the plaintiff establish a cer-
tainty above 50% that the allegations against a defen-
dant are true. In addition, in cases of deprivation of
liberty, such as civil commitment, denaturalization,
deportation, and termination of parental rights, the
standard of “clear and convincing evidence” is also
used. This third standard is intended to be an interme-
diate threshold that falls between the other two and
has been interpreted as requiring a certainty level
between 67% and 75%. Although some research has
shown that jurors provide estimates of the meaning of
reasonable doubt that are close to those given by
members of the legal community, there is still consid-
erable variability in the estimates provided. In addi-
tion, jurors express considerably more variability
(reflecting greater uncertainty) when asked to esti-
mate the meaning of the preponderance of evidence
and clear and convincing evidence standards. Courts
do not typically elaborate on the meaning of standards
of proof when jurors are instructed. In cases where
definitions of the concepts are given, the explanations
typically do not shed much light on the concepts (e.g.,
for reasonable doubt: a doubt “that is not trivial or396 ———Juries and Judges’ InstructionsJ-Cutler (Encyc)-45463.qxd 11/18/2007 12:43 PM Page 396