The Relative Persuasiveness of Different Message Types Does Not Vary as a Function of the Persuasive Outcome Assessed: Evidence from 29 Meta-Analyses of 2,062 Effect Sizes for 13 Message Variations

Experiments that compare the persuasiveness of two message types (e.g., strong vs. weak fear appeals) characteristically examine persuasive impact using attitudinal, intention, or behavioral outcomes. The equivalence of these three outcomes as indices of relative persuasiveness is assessed by re-analyzing data from 2,062 effect sizes in 29 meta-analyses of 13 different message variations, including one-sided and two-sided messages, negative political advertising, and several fear appeal variations. The relative persuasiveness of alternative message types is found to be largely invariant across these different outcomes: If message type A is more persuasive than message type B with attitudinal outcomes, it is also—and equally—more persuasive with intention and behavioral outcomes. Methodological and theoretical implications are discussed.