We find anecdotal evidence to be more persuasive than statistical evidence when emotional engagement is high, as when issues involve a severe threat, health, or oneself

When poignant stories outweigh cold hard facts: A meta-analysis of the anecdotal bias. Traci H. Freling et al. Organizational Behavior and Human Decision Processes, Volume 160, September 2020, Pages 51-67. https://doi.org/10.1016/j.obhdp.2020.01.006

Highlights
• This meta-analysis explores the impact of evidence type on persuasion in 61 studies.
• Overall, statistical evidence exerts a greater impact on persuasion than anecdotal evidence.
• The main effect of evidence type on persuasion is moderated by important contextual variables.
• We find anecdotal evidence to be more persuasive than statistical evidence when emotional engagement is high, as when issues involve a severe threat, health, or oneself.
• We propose that factors which heighten emotional engagement render decision makers more susceptible to the anecdotal bias.

Abstract: The objective of this paper is to resolve mixed findings about which type of evidence is more persuasive—statistical or anecdotal information. In a meta-analysis of 61 papers exploring the persuasive impact of evidence type, we establish that, in situations where emotional engagement is high (e.g., an issue associated with a severe threat, involving a health issue, or affecting oneself), statistical evidence is less influential than anecdotal evidence. However, in situations where emotional engagement is relatively low (e.g., an issue associated with low threat severity, involving a non-health issue, or affecting others), statistical evidence is more persuasive than anecdotal evidence. We discuss the theoretical and practical implications of these findings, and how to improve persuasive messaging by considering the contextual effectiveness of both anecdotes and statistics.