To the Editor: Dr Gazmararian and colleagues1 identified problems in numeracy, the ability to
understand basic mathematical concepts, and health literacy among managed
care enrollees. Such problems may not be limited to patients. We assessed
numeracy in a convenience sample of 24 physicians, 4 nurses, 12 doctorate
faculty, and 5 medical students attending a grand rounds. Numeracy was assessed
with the following written questions: (1) Imagine that we flip a fair coin
1000 times. What is your best guess about how many times the coin would come
up heads in 1000 flips? (answer: 500 times); (2) In a lottery, the chance
of winning a $10 prize is 1%. What is your best guess about how many people
would win a $10 prize if 1000 people each buy a single ticket for the lottery?
(answer: 10 persons); (3) In ACME sweepstakes, the chance of winning a car
is 1 in 1000. What percentage of tickets to ACME sweepstakes win a car? (answer:
0.1%); (4) If you have 5-mg pills of warfarin sodium and you take 7.5 mg/d,
how many of those pills should you take every day? (answer: 1.5 pills); (5)
You have 5-mg pills of warfarin and you take 7.5 mg/d. If you have 9 pills
left, would you have enough for 1 week? (answer: no); and, (6) Your international
normalized ratio should be 2 to 3. If your international normalized ratio
today is 3.5, would your international normalized ratio be low, normal, or
high? (answer: high). The first 3 questions had been used in a study that
examined the role of numeracy in understanding breast cancer screening.2 The last 3 questions are now being used in a study
to assess the role of patients' numeracy skills in the use of warfarin.3