Table 4 Comparison of response completeness by incentive group
Incentive group | Non-incentive group | Association | ||
|---|---|---|---|---|
Multi-item questions (N of items) | Average number of items answered | Rate ratio | 95% CIa | |
Physical health (22) | 20.5 | 20.4 | 0.9 | (0.7, 1.3) |
Posttraumatic stress disorder (17) | 16.7 | 16.8 | 1.3 | (0.7, 2.4) |
Depression (8) | 7.8 | 7.8 | 0.8 | (0.4, 1.5) |
Psychological distress (6) | 5.9 | 5.8 | 0.7 | (0.3 1.5) |
Social support (5) | 4.9 | 4.9 | 0.8 | (0.3, 2.2) |
Dichotomous questions | Proportion answered | Odds ratio | 95% CIa | |
Cancer | 0.985 | 0.978 | 1.5 | (0.7, 3.2) |
Cough | 0.984 | 0.986 | 1.2 | (0.5, 2.9) |
Health insurance | 0.987 | 0.989 | 1.2 | (0.4, 3.2) |
Smoking | 0.986 | 0.983 | 0.8 | (0.4, 1.9) |
Weight | 0.979 | 0.994 | 3.7 | (0.9, 15.0) |