Explaining Jury Verdicts: Is Leniency Bias for Real?

Abstract

Laboratory research suggests juries that begin deliberation with a strong majority (i.e., 2/3 or more) usually end up choosing the verdict favored by this majority, whereas those without a strong majority generally acquit or hang. We tested the robustness of these findings in the field by examining trial and deliberation correlates of jury verdicts using data from 79 criminal jury trials held in Indiana. As expected, several trial characteristics and the first‐vote preference distribution were related to jury verdicts. However, there was no evidence of leniency bias—75% of those juries without a 2/3 majority on the first deliberation vote ended up convicting. Contributions of the study, limitations, and alternative explanations for the observed severity bias are discussed.

Is the leniency asymmetry really dead? Misinterpreting asymmetry effects in criminal jury deliberation

“…In a pair of subsequent studies (Devine et al, 2004;Devine, Buddenbaum, Houp, Studebaker, & Stolle, 2007), Devine and his colleagues responded to their earlier call for more data on this question. Devine et al (2004) surveyed criminal trial jurors immediately after their trials.…”

“…Fortunately, there is potentially a way to empirically resolve these dueling coding assumptions--one might recode these data under different coding assumptions to see if it would alter the degree of leniency vs. severity asymmetry. We first contacted Prof. D. Devine and he sent us the data files for both Devine et al (2004) and Devine et al (2007). Unfortunately, first-ballot undecided or abstain votes were not coded as such for Devine et al (2004) and the raw data were no longer available (D. Devine, personal communications, 15 May 2009 and8 July 2009).…”

“…Thus, Devine et al (2004Devine et al ( , 2007 functionally equated either a vote of "undecided" at the first ballot or an abstention from that first ballot as a preference for a Not Guilty vote at the start of deliberation. Inspection of Sandys and Dillehay's (1995) and Kalven and Zeisel's (1966) methods indicates that they made the same coding assumption as Devine et al (2004Devine et al ( , 2007 What is the net effect of this assumption? Let's consider an example.…”

“…We suspect that one--perhaps the primary--explanation may lie in an apparently innocuous but crucial assumption made in the coding of the field studies' data. Devine et al (2004) state (and justify) this assumption as follows: " … we collapsed the not guilty and uncertain/abstain categories based on the notion that individuals in the latter category were indicating through their behavior Note: Numerical values in the middle columns represent the number of juries arriving at the respective verdict indicated in the column heading given the proportion of jurors favouring conviction on the first vote indicated in the left-hand column. N=103 criminal juries.…”

“…Devine et al (2004) surveyed criminal trial jurors immediately after their trials. There were 97 juries for which data were obtained for at least two jurors; however, for only 79 of these juries was there sufficient agreement among respondents to estimate a first-ballot verdict split (i.e., for approximately 32% of the juries, jurors could not agree on the first ballot vote, even when they were surveyed immediately after that vote).…”