1. Communicating Risk and
Uncertainty
Case study in breast-cancer screening
“Scales of uncertainty”

2. Benefits and harms of cancer
screening
• „Shared-care‟ and „informed choice‟
• New leaflet will present pros and cons
• Will not make recommendation

5. Citizen‟s „Jury‟
• Scientific review used evidence to try to answer
question
„What is the effect of being invited for screening?‟
• But relevant question for women is
„What is the effect of attending screening‟
• Preferred „over-treatment‟ to „over-diagnosis?‟ etc
• Etc etc

6. Uncertainty
But these numbers are very uncertain!
Full of „conditionalities‟
Not quantifiable as a confidence interval
Best current estimate, but may change

10. Words of Estimative Probability
(WEP)
• NIC scale of likelihood and
confidence

13. How can we communicate deeper uncertainties
due to the quality of the evidence?
Part of GRADE scale used in Cochrane Collaboration and 25
other organisations to assess confidence in estimates of medical
treatment effects

16. Sandman‟s 4 conclusions
1.Don‟t just acknowledge the
uncertainty, proclaim it
1. Proclaim how uncertain you are – from
– “I‟m taking a shot in the dark here” to
– “I‟m almost certain but there are still a few
remaining doubts to clear up.”
2. Distinguish your level of uncertainty now from
the level of uncertainty earlier
1. Come across as human

17. 1990: John Gummer –
„beef is safe‟
1992: three cows in
every 1,000 in Britain
had BSE
1996: government
admits link between
BSE and the human
form of the disease,
new variant CJD