Table 2 Numeracy scale with percentages answering correctly in two studies

Ancker
Question Lipkus et al
(n = 463)
on-line
(n = 100)
Clinic
(n = 62b)
Total
(n = 162)
1. Imagine that we flip a fair coin 1,000 times. What is your best guess about how many times the coin would come up heads? question not scored a 74.0 66.1 71.0
2. Which of the following numbers represents the biggest risk of getting a disease? _ 1 in 100, _ 1 in 1000, _1 in 10 78.2 81.0 54.8 71.0
3. Which of the following numbers represents the biggest risk of getting a disease? _ 1%, _ 10%, _ 5% 83.8 92.0 80.6 87.7
4. If Person A's risk of getting a disease is 1% in ten years, and person B's risk is double that of A's, what is B's risk? 90.5 96.0 71.0 86.4
If Person A's chance of getting a disease is 1 in 100 in ten years, and person B's risk is double that of A's, what is B's risk? 86.6 question not used
5. If the chance of getting a disease is 10%, how many people would be expected to get the disease out of 100? 80.8 95.0 67.7 84.6
6. If the chance of getting a disease is 10%, how many people would be expected to get the disease out of 1000? 77.5 89.0 61.3 78.4
7. If the chance of getting a disease is 20 out of 100, this would be the same as having a ____% chance of getting the disease. 70.4 94.0 53.4 78.4
8. The chance of getting a viral infection is .0005. Out of 10,000 people, about how many of them are expected to get infected? 48.6 60.0 32.3 49.4
1. aIn a sample of 287 veterans who completed a mail questionnaire [6], 54% answered this question correctly.
2. bDoes not include responses of three subjects who were interrupted while completing the online questionnaire; on restarting the test, an unexpected system malfunction prevented their responses from being captured.