Risk Communication - The Illusion of Certainty

How do we picture probability? How can a patient deciding on a course of drugs be expected to translate “a 7% chance of dying” or “a 20% likelihood of negative side-effects” into a meaningful image?

http://www.centre-for-global-dialogue.net/INTERNET/rschwebp.nsf/vwPagesIDKeyWebLu/CHAR-7JGJZH/$FILE/Issue_RiskTalkonriskcommunication_Theillusionofcertainty.pdf