6. Healthcare is…
3rd leading
cause of death
in the US
1,000 lives per day
45 lives per hour
@murzee
7. A radical idea
Avoid
DEATHS &
OVERSPENDING
by avoiding
OVERDIAGNOSIS
OVERTREATMENT
@murzee
8. Why?
Because we are blinding
ourselves to the only
certain property of
medicine
UNCERTAINTY
@murzee
9. How?
Open our eyes to uncertainty in medicine
Learn to manage that uncertainty
Dump “Anything is possible”
@murzee
10. What if the solution were…
Cheap Easy Available
Allow me to introduce you to
uncertainty’s sensible
twin sister…
@murzee
11. A study
• 1,000 people are tested
– 900 lawyers
– 100 engineers
• Jack is chosen at random
– Single, 36 years old, introverted
– Hobbies: reads science fiction and writes
computer programs
Adapted from DeNays&Glumicic, 2008
@murzee
12. What is more likely?
A. Jack is a lawyer
B. Jack is an engineer
@murzee
13. Answer
Engineer
Lawyer
Odds 9:1 in favor of LAWYER
@murzee
15. But doctors are much smarter
than an average person, right?
Surely they don’t fall into
these traps.
@murzee
16. Problem
• A disease occurs in 1 out of 1,000
people
• A test to detect this disease gives
a false positive result in 5% of the
people tested
Casscells W et al. N Engl J Med. 1978;299:999-1001
@murzee
17. Question
What is the chance that a person
found to have a positive result
actually has the disease?
2%33%66%95%
Casscells W et al. N Engl J Med. 1978;299:999-1001
@murzee
18. Answer
• A. 2% AKA PPV (positive predictive value)
• B. 33%
• C. 66%
• D. 95%
Casscells W et al. N Engl J Med. 1978;299:999-1001
@murzee
19. Answer
• A. 2% AKA PPV (positive predictive value)
• B. 33%
• C. 66%
• D. 95% 27 of 60 respondents chose D
Casscells W et al. N Engl J Med. 1978;299:999-1001
@murzee
20. Premature death causes
10%
“Public Health”:
•Behavior
Medical •Socio-economic
30% Genetic •Environment
60% "Public Health"
National Healhtcare Expenditures
3%
Medical
Public Health
97%
@murzee
22. “I think that a failure of statistical thinking is the major intellectual shortcoming of our
universities, journalism and intellectual culture.”
@murzee --Steven Pinker