The differential effects of presenting uncertainty around benefits and harms on treatment decision making

The study aimed to determine the effects of presenting uncertainty of quantitative risk information about medication harms and benefits on intention to take medication and psychosocial outcomes.

147 participants were randomized into four hypothetical scenarios: (1) harm/benefit presented as point-estimates, (2) harm as point/benefit as range, (3) harm as range/benefit as point, (4) harm/benefit as ranges. We assessed participants' intention to take medication, understanding, decisional conflict, and perceived benefit and harm. Participants viewed the scenario again with swapped range vs. point-estimate presentations; intention was re-assessed at time 2.

There were no significant differences in intention across arms (p=0.93). There was an increase in intention to take medication between time 1 and time 2 in arm 4 (both harm/benefit presented as ranges, then point estimates). Understanding was greater when information was presented as point estimates compared to ranges, for both benefit (all questions correct: 74% vs 42%; χ2=15.28, df=2, p<0.001) and harm (all questions correct: 70% vs 43%; χ2=11.19, df=2, p=0.004) CONCLUSION: Changes in benefit information appear to be more influential in changing intention to take medication than harm information. Presenting uncertainty decreases understanding of information.

The findings may help develop optimal ways to present uncertainty.