Table 4.
Effect of geographical distance on recruiter-recruita relationship
| Variable | correlation/odds ratio | Same postal codeb | p value | 1 to 10 kmb | p value | >10 kmb | p value | Overall test |
|---|---|---|---|---|---|---|---|---|
| Age | r | 0.50 [0.39–0.61] | <0.001 (df: 177) | 0.40 [0.25–0.53] | <0.001 (df: 144) | 0.21 [0.06–0.35] | 0.008 (df: 160) | 0.008 |
| Education | r rank | 0.33 [0.19–0.47] | <0.001 (n: 179) | 0.26 [0.09–0.41] | 0.001 (n: 146) | 0.32 [0.15–0.47] | <0.001 (n: 162) | 0.770 |
| Household size | r | 0.40 [0.26–0.51] | <0.001 (df: 177) | 0.08 [−0.09–0.24] | 0.363 (df: 144) | 0.14 [−0.01–0.29] | 0.067 (df: 160) | 0.004 |
| Degree LOG | r | 0.16 [0.01–0.30] | 0.034 (df: 173) | −0.02 [−0.18–0.15] | 0.855 (df: 136) | 0.04 [−0.11–0.20] | 0.583 (df: 154) | 0.264 |
| Belief vaccination protects | r rank | 0.19 [0.04–0.35] | 0.012 (n: 169) | 0.17 [−0.00–0.33] | 0.056 (n: 131) | 0.41 [0.27–0.55] | <0.001 (n: 154) | 0.041 |
| Sex | OR | 0.35 [0.14–0.79] | 0.006 (n: 179) | 4.86 [2.13–11.39] | <0.001 (n: 146) | 1.91 [0.93–3.93] | 0.054 (n: 162) | <0.001 |
| Vaccinated | OR | 4.94 [2.30–11.07] | <0.001 (n: 169) | 3.54 [1.50–8.67] | 0.001 (n: 131) | 1.36 [0.66–2.81] | 0.366 (n: 154) | 0.025 |
| One or more symptoms | OR | 1.09 [0.57–2.11] | 0.771 (n: 169) | 3.03 [1.39–6.80] | 0.002 (n: 131) | 1.36 [0.68–2.72] | 0.349 (n: 154) | 0.093 |
| Self-reported common cold | OR | 1.27 [0.47–3.23] | 0.585 (n: 169) | 1.31 [0.33–4.35] | 0.635 (n: 131) | 1.10 [0.25–3.79] | 0.874 (n: 154) | 0.974 |
| Self-reported influenza | OR | 8.01 [1.98–31.38] | <0.001 (n: 169) | 9.32 [1.22–59.64] | 0.001 (n: 131) | 4.90 [0.73–25.05] | 0.052c (n: 154) | 0.814 |
aNumber of pairs with same postal code (n: 180 pairs), with same Internet Protocol (IP) address (n: 86), and number of pairs with both same postal code and same IP address (n: 72)
bCorrelation coefficients/odds ratios with 95 % confidence intervals are shown
cFisher’s exact test was used for contingency tables containing small values (n < 10)