A Meta-Analysis of Research on Inoculation Theory

A meta-analysis of 54 cases testing the effectiveness of inoculation theory at conferring resistance and examining the mechanisms of the theory was conducted. The analyses revealed inoculation messages to be superior to both supportive messages and no-treatment controls at conferring resistance. Additionally, the results revealed refutational same and refutational different preemptions to be equally effective at reducing attitude change. However, the data were not consistent with some predictions made in narrative reviews of inoculation. No significant increase in resistance as a function of threat or involvement was found. Further, instead of a curvilinear effect for delay on resistance, the point estimates from our meta-analysis revealed equivalent resistance between immediate and moderate delays between inoculation and attack, with a decay in resistance after two weeks.