Patient knowledge and recall of health information following exposure to "facts and myths" message format variations

Objective: To assess if exposure to varying "facts and myths" message formats affected participant knowledge and recall accuracy of information related to influenza vaccination. Methods: Consenting patients (N= 125) were randomized to receive one of four influenza related messages (Facts Only; Facts and Myths; Facts, Myths, and Refutations; or CDC Control), mailed one week prior to a scheduled physician visit. Knowledge was measured using 15 true/false items at pretest and posttest; recall accuracy was assessed using eight items at posttest. Results: All participants' knowledge scores increased significantly (p<0.05); those exposed to the CDC Control message had a higher posttest knowledge score (adjusted mean=11.18) than those in the Facts Only condition (adjusted mean 9.61, p=<0.02). Participants accurately recalled a mean of 4.49 statements (SD=1.98). ANOVA demonstrated significant differences in recall accuracy by condition [F(3, 83)=7.74, p < .001, η²=0.22]. Conclusion: Messages that include facts, myths, and evidence to counteract myths appear to be effective in increasing participants' knowledge. We found no evidence that presenting both facts and myths is counterproductive to recall accuracy. Practice implications: Use of messages containing facts and myths may engage the reader and lead to knowledge gain. Recall accuracy is not assured by merely presenting factual information.