LAUSR

Background Pretesting is the key to understanding how the intended audience will react to the message. Resistant reactions affect message processing or can lead to undesirable boomerang effects. The objective of this study was to develop a rating scale for measuring active (reactance) and passive (disengagement) resistance to persuasive health messages. Methods Six candidate items (3 items for disengagement and 3 items for reactance) were generated based on literature review. A web-based survey was conducted among Japanese adults aged 25–64 years to verify the reliability and validity of the 6-item resistance scale. Participants were asked to rate one of the advance care planning (ACP) promotion messages. All scale items were scored on a 1-to-5 point Likert scale and they were averaged to produce the resistance score. Results Explanatory factor analysis revealed a two-factor solution that agreed with the disengagement and reactance domains, respectively. Correlation coefficients between each set of items ranged between 0.30–0.69. Cronbach alpha (0.86) indicated satisfactory internal consistency of the set of items. Confirmatory factor analysis showed a good fit of the two-factor model with CFI = 0.998, SRMR = 0.011, and RMSEA = 0.041. The resistance score showed a moderate positive correlation with negative emotional responses (displeasure γ = 0.55, anger γ = 0.53) and was significantly inversely related to the persuasiveness score (γ = −0.50). Multivariable logistic regression analysis showed that the odds ratio for ACP intention per 1-point increase in the resistance score was 0.47 (95% confidence interval 0.40–0.56) with adjustment for the persuasiveness score. Conclusion The 6-item resistance scale exhibited adequate reliability and validity for measuring audience resistance when applied to the ACP promotion messages in Japanese people. The scale will be useful for pretesting health messages to make them more acceptable to the intended audience. Trial registration Not applicable; this is not a report of intervention trial. Supplementary information The online version contains supplementary material available at https://doi.org/10.1265/ehpm.22-00059.