Efficacy and usability of the informed consent process of study participants randomised to multimedia intervention or control delivery of study information and informed consent
| Variable | Control (n=152) | Intervention (n=146) | P value |
| Efficacy, participants understood | |||
| Taking part was completely voluntary, n (% yes) | 150 (99) | 144 (99) | 0.167 |
| The right to withdraw from the study at any time, n (% correct) | 143 (94) | 136 (93) | 0.893 |
| Baseline participation requirements, n (% correct) | 149 (98) | 144 (99) | 0.090 |
| Follow-up participation requirements, n (% correct) | 82 (54) | 118 (87) | <0.001 |
| Data sharing with referring practitioner, n (% correct) | 132 (87) | 136 (93) | 0.025 |
| Usability | |||
| Engaged with the study information, n (%) | 106 (70) | 117 (80) | <0.001 |
| Perceived understanding of the study could be improved, n (%) | 28 (18) | 16 (11) | 0.077 |
| Successfully completed the consent process, n (%) | 152 (100) | 146 (100) | 1 |
| Total duration (min) (range) | 8.4 (2.1–30.5) | 9.6 (3.3–17.3) | 0.006 |
Data are expressed as percentages of the group total. P values relate to the χ2 test used for the comparison of categorical variables and t-test was used for continuous variables.