Table 4.
Comparison of subjects’ understanding of research procedures and design, by motivation and doctor status.
| Motivation | Doctor Status | |||
|---|---|---|---|---|
| Responses (N (%)) | Direct personal benefit N= 54a | Altruism/dual N= 35a | Own doctor N= 39a | Other N= 49a |
| How is it decided who will receive the experimental treatment vs. sham surgery? | ||||
| Random assignment | 39 (75.0) | 29 (82.9) | 31 (81.6) | 35 (74.5) |
| Subject mentions some method other than random assignment | 4 (7.7) | 3 (8.6) | 2 (5.3) | 5 (10.6) |
| Subject not sure | 9 (17.3) | 3 (8.6) | 5 (13.2) | 7 (14.9) |
| What were the chances of a subject being assigned to the sham surgery group? | ||||
| Correct answer | 43 (82.7) | 30 (90.9) | 33 (86.8) | 39 (84.8) |
| Incorrect answer | 4 (7.7) | 2 (6.1) | 2 (5.3) | 4 (8.7) |
| Subject not sure | 5 (9.6) | 1 (3.0) | 3 (7.9) | 3 (6.5) |
| What is the purpose of having a sham surgery group? sham condition? Why do researchers need to have a | ||||
| Mentions or describes need to control for placebo effect | 36 (67.9) | 19 (54.3) | 23 (60.5) | 30 (61.2) |
| Mentions to make study legitimate/rigorous (no mention or description of placebo effect) | 10 (18.9) | 14 (40.0) | 10 (26.3) | 15 (30.6) |
| Mentions that FDA requires it | 1 (1.9) | 1 (2.9) | 1 (2.6) | 1 (2.0) |
| Can't determine from text if subject understands purpose of sham surgery (response unclear) | 2 (3.8) | 1 (2.9) | 1 (2.6) | 2 (4.1) |
| Subject not sure | 2 (3.8) | 0 (0) | 1 (2.6) | 1 (2.0) |
| Other | 2 (3.8) | 0 (0) | 2 (5.3) | 0 (0) |
| Describe the difference in procedures between those who receive sham surgery and those who receive the experimental intervention. | ||||
| Correct answer (describes difference between two arms accurately) | 42 (89.4) | 25 (80.6) | 25 (80.6) | 40 (88.9) |
| Incorrect answer | 2 (4.3) | 2 (6.5) | 2 (6.5) | 2 (4.4) |
| Not sure | 3 (6.4) | 3 (9.7) | 3 (9.7) | 3 (6.7) |
| Other | 0 (0) | 1 (3.2) | 1 (3.2) | 0 (0) |
a
Denominator varies because of missing data for some questions.
Fisher’s exact tests did not show differences in the responses for any of the four questions for understanding of research procedures by motivation or by doctor status.