| Reporters | Change in odds of non-response per membership year* | Change in odds of zero return per calendar year† | Change in odds of zero return per year of membership‡ | Change in odds of zero return per calendar year‡ |
| OPRA 1996–2005 | 1.04 (1.02 to 1.07) | 0.94 (0.92 to 0.96) | 1.06 (1.01 to 1.11) | 0.90 (0.86 to 0.94) |
| EPIDERM 1996–2005 | ||||
| Core | 1.06 (0.97 to 1.15) | 1.04 (0.99 to 1.10) | 0.99 (0.94 to 1.04) | 1.05 (0.96 to 1.16) |
| Sample | 1.07 (1.02 to 1.12) | 1.02 (0.98 to 1.07) | 1.05 (0.99 to 1.11) | 0.99 (0.94 to 1.04) |
| SWORD 1999–2005 | ||||
| Core | 1.07 (1.02 to 1.13) | 0.97 (0.90 to 1.05) | 1.03 (0.94 to 1.12) | 0.95 (0.84 to 1.06) |
| Sample | 1.09 (1.05 to 1.13) | 1.07 (1.03 to 1.12) | 1.02 (0.98 to 1.05) | 1.06 (1.02 to 1.12) |
*Marginal logistic model included membership time, season and new reporter variable. †Returned cards only; marginal logistic model included calendar time, season and new reporter variable. ‡Returned cards only; marginal logistic model included membership time, calendar time, season and new reporter.