We report the results of four experiments investigating the relationship between (1) the quality of an audit, (2) jurors' assessments of the standard of prudent care (SOC) against which audit quality is compared, and (3) jurors' negligence verdicts. Experiment 1 operationalizes audit quality by varying the sample size used in audit testing, and provides evidence that jurors anchor their assessment of SOC on audit quality, producing a "competitive mediation" in which audit quality reduces the potential for a negligence verdict directly, but increases that potential indirectly by increasing SOC. Experiment 2 generalizes this finding to a setting that operationalizes audit quality by varying the size of adjustment the auditor required. Experiments 3 and 4 extend these results to a setting in which SOC is elicited after jurors make negligence verdicts. Overall, these experiments provide insight into the role of SOC in constraining and justifying negligence verdicts.