Table 2

Questionnaire items, correct response rate, and factor loading for each item for Schwartz-J and LipkusJ
Question Answered correctlya Schwartz-Jc Lipkus-Jd
Factor loadingb Communality (h2) Factor loadingb Communality (h2)
1 Imagine that we rolled a fair, six-sided die 1,000 times. Out of 1,000 rolls,how many times do you think the die would come up even (2, 4, or 6)? 85(55) 0.66 0.43 0.68 0.46
2 *In a lottery, the chance of winning a 1,000 yen prize is 1%.What is your best guess about how many people would win a 1,000 yen prize if 1,000 people each buy a single ticket to this lottery? 82(60) 0.74 0.55 0.63 0.40
3 *In a lottery, the chance of winning a car is 1 in 1,000. What percent of tickets to this lottery win a car? 73(21) 0.66 0.43 0.61 0.37
4 Which of the following numbers represents the biggest risk of getting a disease? 1 in 100, 1 in 1000, 1 in 10 95(78) 0.90 0.81
5 Which of the following numbers represents the biggest risk of getting a disease? 1%, 10%, 5% 97(84) 0.82 0.67
6 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? 92(91) 0.78 0.61
7 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? 90(87) 0.71 0.50
8 If the chance of getting a disease is 10%, how many people would be expected toget the disease:A: Out of 100? 92(81)
9 If the chance of getting a disease is 10%, how many people would be expected toget the disease:B: Out of 1000? 91(78) 0.77 0.60
10 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. 93(70) 0.77 0.59
11 The chance of getting a viral infection is .0005. Out of 10,000 people, about how many of them are expected to get infected? 69(49) 0.18 0.03

aPercentage of participants who responded correctly to each item. Corresponding values on the original American study are shown in parentheses ([15], n = 463).

bFactor loadings are shown as pattern matrix.

cFor Schwartz-J, one factor consisting of all three items accounted for 47.1% of variance.

dFor Lipkus-J, one factor consisting of 9 items accounted for 55.6% of variance.

*Slightly modified from the original for the Japanese context.

Okamoto et al.

Okamoto et al. BMC Medical Informatics and Decision Making 2012 12:104   doi:10.1186/1472-6947-12-104

Open Data