Table 3.
| Comprehension subscale and items (correct response) | Low literacy (n = 40)b | High literacy (n = 52) | Effect sizec | Pd value |
|---|---|---|---|---|
| Mean % correct | ||||
| Privacy (two items)e | 35.0 | 47.0 | 0.46 | 0.030 |
| Only staff from the hospital or clinic can look in your medical records for information about your treatment. (F) | 5.0 | 15.4 | ||
| Published information about this study may include your name. (F) | 65.0 | 78.8 | ||
| Side effects (three items)e | 88.3 | 95.0 | 0.37 | 0.060 |
| The drugs that are part of the study may cause your hair to fall out. (T) | 92.5 | 96.2 | ||
| The drugs in the study will have no effect on your level of energy. (F) | 85.0 | 94.2 | ||
| The side effects from the drugs will affect all patients in the same way. (F) | 87.5 | 94.2 | ||
| Personal benefit (six items)e | 65.8 | 71.8 | 0.29 | 0.095 |
| The consent form stated that the study is being done to find the treatment that will most benefit you. (F) | 25.0 | 27.5 | ||
| According to the consent form the purpose of the study is to see which of the treatments being tested is better at slowing the growth of your disease. (T) | 92.5 | 96.2 | ||
| According to the consent form the reason the study is being conducted is to find the treatment that will cure your disease. (F) | 37.5 | 61.5 | ||
| It is unlikely that the drugs that are part of the study will cure your disease. (T) | 62.5 | 65.4 | ||
| The drugs that are part of the study might not be better for treating your disease than other drugs that are available. (T) | 92.5 | 86.5 | ||
| Your disease will be cured as a result of the treatment study. (F) | 85.0 | 94.2 | ||
| Benefit to others (one item)e | 100.0 | 98.0 | −0.20 | 0.395 |
| What is learned from the treatment study will help future patients. (T) | ||||
| Choice (four items)e | 79.5 | 87.5 | 0.41 | 0.012 |
| It’s up to you to decide if your will be part of the treatment study. (T) | 97.5 | 98.1 | ||
| If you agree to be part of the study you must stay on the treatment until the study is over. (F) | 40.0 | 73.1 | ||
| There are no treatment options for your disease other than this study. (F) | 80.0 | 84.6 | ||
| You could choose not to have any treatment at all. (T) | 100.0 | 94.2 | ||
| Financial (two items)e | 50.0 | 68.5 | 0.49 | 0.027 |
| You may be responsible for some of the treatment costs not covered by your insurance or the study. (T) | 62.5 | 76.9 | ||
| You will be paid for taking part in the treatment study. (F) | 37.5 | 59.6 | ||
| Randomization (one item)f | 45.0 | 69.0 | 0.48 | 0.022 |
| If you agree to be part of the treatment study, how is it decided what treatment group you are in? (3: Chosen by chance) | ||||
| Reason off-study (one item)e | 8.0 | 13.0 | 0.16 | 0.371 |
| The only reason you will be taken off the study, or have your treatment changed, is if the drugs make you so sick that it’s unbearable. (F) | ||||
| Total (20 items) | 65.0 | 73.9 | 0.65 | <0.001 |
Notes:
a
Low literacy: below seventh-grade reading level; high literacy: seventh-grade level and above 34;
b
Data were missing for five low-literacy patients who did not complete the comprehension interview;
c
Effect size: mean difference between groups (high literacy minus low literacy), divided by the common standard deviation;
d
P value for Wilcoxon rank-sum test to compare comprehension scores between low- and high-literacy groups;
e
Item response scale: T = true, F = false;
f
Item response scale: 1 = you decide on the treatment group, 2 = your doctor decides on the treatment group, 3 = the treatment group is chosen by chance.