(69) Visualizing very small risks

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Some risk communication situations require helping people to visualize just how rare very rare events are. A common example occurs in prenatal genetic testing. If a couple has no other risk factors, the baseline risk of genetic diseases such as Down Syndrome is often much smaller than even 1 in 1000 (0.1%). Visually showing this ratio is challenging.

What’s special about this image?

This display uses matrices of squares to represent the full probability space and a callout to reinforce how small the individual risk is.
  • My goal
  • Raise or lower concern
  • Awareness of risk
  • Details or gist?
  • Verbatim recall
  • Data I have
  • Test result
  • Risk estimate
  • Health conditions
  • Down syndrome
  • Graphic type
  • Icon array
  • Area graph
  • Callout