The power of meaningful numbers: Attorney guidance and jury deliberation improve the reliability and gist validity of damage awards.

Objective: A mock jury experiment tested the effects of attorney guidance and jury deliberation to mitigate the challenges that civil juries face in assessing damages.

Hypotheses: We hypothesized that two types of attorney guidance (per diem, per diem + lump sum), theoretically based in the Hans-Reyna model of jury decision making, would improve jury decision making compared with no guidance against five key benchmarks: injury assessment, validity, reliability, verbatim-gist coherence, and metacognitive experience. We expected that deliberation would increase reliability of, confidence in, and polarization of awards compared with predeliberation.

Method: Community members ( = 317; 61% women; 86.1% White; M = 48.68 years) deliberated in 54 mock juries. Participants watched a videotaped trial involving an automobile accident in which two plaintiffs sustained concussions (one mild and one severe). The plaintiffs' attorney's closing arguments varied attorney guidance (no guidance, per diem, per diem + lump sum). Mock jurors provided individual judgments before deliberating as a jury and reaching group verdicts and awards.

Results: Juries performed well against benchmarks. Providing gist-based guidance with a meaningful award recommendation increased the validity of jurors' individual damage awards (η² = .03) and the reliability of jury damage awards (η² = .04; η² = .20); gist-based guidance without an award recommendation did not improve performance against benchmarks and increased perceptions of decision-making difficulty (η² = .13). Deliberation increased reliability of (η² = .17), confidence in (η² = .02), and polarization of ( = 2.14) awards compared with predeliberation.

Conclusion: Juries performed well against objective benchmarks of performance (injury assessment, validity, reliability, and verbatim-gist coherence), and deliberation improved performance compared with predeliberation decisions. Jury decisions were further influenced by attorney closing arguments (the guidance manipulation), especially when the attorney requests a lump sum, which can serve as a powerful influence on jury awards, mainly by setting an upper limit. (PsycInfo Database Record (c) 2024 APA, all rights reserved).