1. How People Respond to Risk
James Neuberger

2. Facts are stubborn things but statistics are plastic (Mark Twain)
Errors using inadequate data are much less than those not using data at all (Charles Babbage)
99% of all statistics only tell 49% of the story (Ron Delease)
Politicians use statistics like some alcoholics use lampposts – more for support than for illumination (Andrew Lang)

3. Communication is a two way process
Failure of communication is not the fault of just one person

4. GMC Guidance
You must not make assumptions about a patient’s understanding of risk or the importance they attach to different outcomes
You must tell patients if … a treatment might result in a serious adverse outcome, even if the likelihood is very small. You should also tell patients about less serious complications if they occur frequently
An adverse outcome resulting in death, permanent or long term physical disability or disfigurement, medium or long-term pain… or other outcome with a long-term effect on a patient’s employment, social or personal life

5. People’s response to risk is variable
Response to risk depends on many factors including
Familiarity
Control
Personal experience (and other heuristics)
Dread
Emotional state of person (valence theory)

6. Common biases and heuristics (Kahneman and Tversky)
Availability
Events that can be more readily brought to mind considered more likely
Representativeness
Insensitivity to prior, size,
Anchoring
Adjust unknown on basis of known
Asymmetry
Different approaches to gains and losses, preferring certain gain over gamble with higher utility
Threshold
Different choices for similar gain

7. People’s response to risk is variable
“I am going horse riding but won’t sit in row 13 on the bus”
After 9/11, more people in US drove than flew, resulting in an estimated 1000 excess deaths
“I will not eat beef (because of vCJD) but will continue to smoke”

8. Presentation
Be aware that the order in which risks and benefits are presented may affect risk perceptions
Be aware that comparative risk information is persuasive and not just informative
Repeatedly draw attention to the time interval over which the risk occurs

9. From RCoA

14. NHS Booklet on Breast Screening

16. How to phrase the risk Framing is important Response to surgery
There is a 90% chance that you will be alive 1 year after bypass surgery
There is a 10% chance you will die from the surgery

17. so Data can be presented in many ways Avoid using %
Avoid using terms like common or rare
Put the figures in context
1 in 100 rather than 1%
1 person in a town like Warwick rather than 1 in 30000

18. Explaining risk 5% risk 1 in 20 chance 5 out of 100 people like you
5 out of 100 ways things may turn out for you

19. Be careful
More information and information that is understandable to the patient is associated with a greater wariness to the treatment and tests
Deaths rates of 1286 out of were rated as more risky than out of 100

20. Other tips People’s biases Understanding of figures
‘Now that I know of confirmation bias, I see examples all around me’ (Jon Ronson)
Understanding of figures
Many people think a risk of 1:25 is greater than 4:100
Those people tend to be less interested in shared-care / informed-choice
Many suggest written information should aim for those with a reading age of 8-10

21. The micromort: unit of risk (Spiegelhalter)
A 1 in chance of sudden death

24. Conclusions Use plain language
Present data using absolute risks and frequencies
Consider use of images such as pictographs
Consider use tables that include tables summarising all benefits and risks
Consider using incremental formats where appropriate
Consider presenting information that is most critical for decision making at the expense of completeness

25. References and thanks Fagerlin A, et al. JNCI 2011
Edwards et al, BMJ 2002
Yamagishi Appl Cog Psyhcol 1997
Galesic Health Psychology 2011
Sir David Spiegelhalter
Prof Chris Watson
NHSBT
Alex Hudson
Dr Matthew Robb