Background: Patients must be informed about risks before any treatment can be implemented. Yet serious problems in communicating these risks occur because of framing effects.
Objective: To investigate the effects of different information frames when communicating health risks to people with high and low numeracy and determine whether these effects can be countered or eliminated by using different types of visual displays (i.e., icon arrays, horizontal bars, vertical bars, or pies).
Design: Experiment on probabilistic, nationally representative US (n = 492) and German (n = 495) samples, conducted in summer 2008.
Outcome measures: Participants' risk perceptions of the medical risk expressed in positive (i.e., chances of surviving after surgery) and negative (i.e., chances of dying after surgery) terms.
Key results: Although low-numeracy people are more susceptible to framing than those with high numeracy, use of visual aids is an effective method to eliminate its effects. However, not all visual aids were equally effective: pie charts and vertical and horizontal bars almost completely removed the effect of framing. Icon arrays, however, led to a smaller decrease in the framing effect.
Conclusions: Difficulties with understanding numerical information often do not reside in the mind, but in the representation of the problem.