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David Spiegelhalter, Cambridge University - #steps13


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David Spiegelhalter, Cambridge University - #steps13

  1. 1. Communicating Risk and UncertaintyCase study in breast-cancer screening“Scales of uncertainty”
  2. 2. Benefits and harms of cancer screening• „Shared-care‟ and „informed choice‟• New leaflet will present pros and cons• Will not make recommendation
  3. 3. 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
  4. 4. UncertaintyBut these numbers are very uncertain!Full of „conditionalities‟Not quantifiable as a confidence intervalBest current estimate, but may change
  5. 5. Words of Estimative Probability (WEP)• NIC scale of likelihood and confidence
  6. 6. How can we communicate deeper uncertainties due to the quality of the evidence?Part of GRADE scale used in Cochrane Collaboration and 25other organisations to assess confidence in estimates of medicaltreatment effects
  7. 7. Sandman‟s 4 conclusions1.Don‟t just acknowledge the uncertainty, proclaim it1. 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 earlier1. Come across as human
  8. 8. 1990: John Gummer – „beef is safe‟1992: three cows inevery 1,000 in Britainhad BSE1996: governmentadmits link betweenBSE and the humanform of the disease,new variant CJD