about their accuracy. In conclusion, three of the five
reports are distorted by simple, legal comments from
investigators.Description and Time:
Objective Reports
Description and time are primarily objective reports—
evaluations of these criteria do not rely on witnesses’
own reports. Evaluators can examine for themselves the
degree of match between a witness’s description and
the appearance of the defendant. Similarly, there is a
record of the date of the crime and the date the suspect
was positively identified. Psychological literature gen-
erally supports the time criterion: Accuracy diminishes
as the time between the witnessed event and the identi-
fication attempt increases. However, the literature on
the description criterion is mixed. One study concluded
that there is no connection between an eyewitness’s
description and identification accuracy. Other studies
suggest that witnesses are more likely to identify sus-
pects if the witnesses have given a detailed description.
Still other studies complicate the relationship even fur-
ther by suggesting that the mere process of providing a
verbal description of a perpetrator harms identification
accuracy (i.e., verbal overshadowing). An empirically
validated interviewing style, known as the cognitive
interview, increases the quality of witnesses’ descrip-
tions but, as predicted by verbal overshadowing,
decreases identification accuracy. Fortunately, identifi-
cation accuracy rates are preserved if a delay exists
between the verbal description and the identification
attempt. Even though description and time are primar-
ily objective, they are not immune to influence by
external variables such as interviewing style.System Variables Versus
Estimator Variables
Most of the Biggerscriteria are estimator variables—
that is, variables that are not under the control of the
justice system. For example, the justice system has no
control over what kind of view the eyewitness had of
the culprit. Similarly, the justice system has no control
over how much or what kind of attention the witness
paid to the culprit. In contrast, the time criterion falls
into the system variable category—that is, variables
that the justice system can control. For example,
investigating officers can decide whether to show pho-
tos to a witness immediately after a crime is reportedor wait until a suspect is located for a live lineup. The
ability to make these decisions means that time is a
system variable rather than an estimator variable.
The two remaining variables, confidence and
description, straddle both categories. In some ways,
they are estimator variables because the justice system
cannot ensure that crime characteristics lead to high
confidence or good descriptions (e.g., by ensuring that
the culprit is in view for a long time and has no dis-
guise). However, both criteria have system variable ele-
ments. Confidence can be easily manipulated by
external factors having nothing to do with identification
accuracy. Myriad variables, such as postidentification
feedback, co-witness information, and repeated ques-
tioning, affect eyewitnesses’ confidence. The quality of
a witness’s description is also influenced by external
variables such as the style of interviewing. The cogni-
tive interview increases both the amount and the qual-
ity of information gathered from eyewitnesses.The BBiiggggeerrssCriteria Attempt
to Postdict Accuracy
The final problem with the Biggerscriteria is that they
attempt to postdict accuracy—that is, to determine
from eyewitnesses’ own reports whether an identifica-
tion that had already occurred was accurate or inaccu-
rate. Empirical research reveals limited success in
postdicting accuracy. This will be especially difficult
when the variables intended to postdict accuracy are
so vulnerable to distortion. A preferable strategy is to
minimize the likelihood of inaccurate identifications
at the time of the confrontation. One clear example of
such a change is to require investigators to warn eye-
witnesses that the culprit might or might not be pre-
sent in the set of photos. Another is to obtain a report
of the witness’s confidence immediately after the
identification is made, allowing defense attorneys to
challenge inflated confidence reports at trial.
The continuing publicity surrounding DNA exon-
erations of individuals wrongfully identified should
impress on the Court the need to revisit the Biggers
criteria. Should the Court undertake such a challenge,
some preference for system variable changes would
likely be articulated by many psycholegal researchers.
In the meantime, defense attorneys and expert wit-
nesses alike should continue to challenge the utility of
these criteria, especially confidence, in contributing to
meaningful evaluations of eyewitness identification
accuracy. At best, the criteria outlined by the CourtNNeeiill vv.. BBiiggggeerrss Criteria for Evaluating Eyewitness Identification——— 525N-Cutler (Encyc)-45463.qxd 11/18/2007 12:43 PM Page 525