Juror Ratings of Risk Appear Dependent Upon Communication Format in Static-99R Reports

Jorge G. Varela, Marcus T. Boccaccini, Sam Houston State University
Veronica A. Cuervo, Sam Houston State University
Daniel C. Murrie, University of Virgina
John W. Clark, University of Texas at Tyler

The popular Static-99R allows evaluators to convey results in terms of risk category (e.g., low, moderate, high), relative risk (compared with other sexual offenders), or normative sample recidivism rate formats (e.g., 30% reoffended in 5 years). But we do not know whether judges and jurors draw similar conclusions about the same Static-99R score when findings are communicated using different formats. Community members reporting for jury duty (N 211) read a tutorial on the Static-99R and a description of a sexual offender and his crimes. We varied his Static-99R score (1 or 6) and risk communication format (categorical, relative risk, or recidivism rate). Participants rated the high-scoring offender as higher risk than the low-scoring offender in the categorical communication condition, but not in the relative risk or recidivism rate conditions. Moreover, risk ratings of the high-scoring offender were notably higher in the categorical communication condition than the relative risk and recidivism rate conditions. Participants who read about a low Static-99R score tended to report that Static-99R results were unimportant and difficult to understand, especially when risk was communicated using categorical or relative risk formats. Overall, results suggest that laypersons are more receptive to risk results indicating high risk than low risk and more receptive to risk communication messages that provide an interpretative label (e.g., high risk) than those that provide statistical results.

: Static-99R, communication, risk assessment, sexual offender

Risk and recidivism of sexual offenders has become a captivating topic in psychology and law, prompting an increase in research surrounding risk assessment. However, discrepancies between actual sexual recidivism and public perception of risk necessitate research regarding the effectiveness of expert communication of risk to juries. Varela, Boccaccini, Cuervo, Murrie, and Clark examined juror interpretation of varying Static-99R score communication formats to investigate whether these factors impact layperson perception of sexual offender risk.

The Static-99R is a risk assessment tool utilized frequently by forensic evaluators to report on the level of risk of an individual brought to the criminal justice system. This instrument “allows evaluators to convey results in terms of risk category (e.g., low, moderate, high), relative risk (compared with other sexual offenders), or normative sample recidivism rate formats (e.g., 30% reoffended in 5 years).” However, little is know about whether judge and juror interpretation of Static-99R scores is dependent upon communication format.

Based on previous research findings that judges and jurors may be confused by statistical explanations of risk and seem to devalue expert opinions that indicate low risk of violence, the current study “compared the influence of three Static-99R risk communication formats—categorical, risk estimate, and relative risk—on venirepersons’ perceptions of sexual offenders” (p. 420). A final sample of 211 prospective jurors read one of six case descriptions, which “varied across two dimensions—the offender’s Static-99R score (i.e., risk level) and risk communication format. The low-scoring offender was assigned a Static-99R score of 1 and the high-scoring offender was assigned a Static-99R score of 6” (p. 420).

“After reading the case description and Static-99R results, participants were asked to make three ratings related to the hypothetical offender—likelihood of committing a new sexual offense in the next 5 years, dangerousness to community members, and support for the use of the “most strict and expensive supervision strategies.” They rated each of these items on a scale ranging from 1 (not likely at all/not at all dangerous) to 6 (very likely/very dangerous). Based on previous research examining jurors’ perceptions of offender risk (e.g., Boccaccini, Murrie, Clark, & Cornell, 2008), we expected that ratings on these items would be moderately to highly correlated and that we would combine them to form a single risk composite variable. In other words, those who view the offender as likely to reoffend should also view him as dangerous to the community and in need of the most strict supervision strategies” (p. 420).

The authors found that ratings on the three items were, in fact, moderately to strongly correlated. However, “Participants rated the low-scoring offender as lower risk than the high-scoring offender in some but not all of the communication format conditions. When risk communication was in the form of a categorical message, participants assigned lower risk ratings to the low-scoring offender than the high-scoring offender. When the risk communication was in the form of a relative risk message, participants assigned only somewhat lower risk ratings to the low-scoring offender. Finally, when presented a recidivism rate message, participants assigned nearly identical risk ratings to the low- and high-scoring offenders. Overall, these findings indicate that participants viewed the high- and low-scoring offenders as having significantly different levels of risk when Static-99R results were communicated using a categorical format, but not when results were communicated using relative risk or recidivism rate formats” (p. 421).

Taken together, the results indicate that varying risk communication formats of the Static-99R may result in different conclusions drawn by legal decision-makers.

The finding that prospective jurors rated the high-scoring hypothetical offender as more dangerous and more likely to reoffend when risk was communicated categorically as opposed to numerically should raise awareness to forensic evaluators about effective communication formats. The finding that the prospective jurors in this study rated the low-scoring hypothetical offender as “similarly likely to reoffend” as the high-scoring offender when the risk information was presented numerically has serious implications. The authors suggest that this may be the result of layperson overestimation of risk or layperson misunderstanding and misapplication of numerical data. Regardless, practitioners who perform Static-99R evaluations and testify in court proceedings should consider this research and take caution in the communication format they choose to utilize. It appears that jurors may be more receptive to categorical communication formats as opposed to formats that involve normative groups or statistical explanations.

Additionally, since “findings also suggest that venirepersons either neglect risk ratios or do not understand them, especially when the risk ratio suggests low risk,” clinicians in this field should take care in communicating low-risk findings to ensure optimal juror understanding (p. 425). Though evaluators may not necessarily be able to reverse layperson overestimation of risk, attempts to clarify may assist in legal decision-making. “Researchers and clinicians in forensic psychology are understandably focused on developing and properly using instruments, including actuarial instruments. But until the field can communicate to decision makers the results of these measures—in understandable and constructive ways—the practical value of rigorous assessment methods will be greatly constrained” (p. 425).

“Confirmation bias may help explain the varied pattern of participants’ responses to risk communication messages. Confirmation bias is the tendency to selectively seek and interpret information in a manner consistent with one’s beliefs and expectations. In our study, nearly all participants, across all experimental conditions, reported that the offender would likely reoffend within the next 5 years. It is reasonable to assume that many participants in our study assumed that most sexual offenders reoffend, as have participants in other research. Therefore, a risk communication indicating that a sexual offender was at low risk for reoffending would have been incongruent with participants’ expectations about sexual offenders and easy to dismiss as unpersuasive or difficult to understand. These findings add to the small but growing body of research suggesting that judges and jurors may simply discount or devalue low-risk messages, perhaps because low-risk messages are incongruent with their expectations that those who have offended in the past will offend again” (p. 424).

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