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Table 3 Results of the regression models for respondent interest in participating in the field study

From: Effectiveness of incentives and follow-up on increasing survey response rates and participation in field studies

Model and test relative to intercept-only model Variable Fixed effects Variable level Interest in field study
df Wald χ2 p-value p-value OR 95% CI
Model 1
χ2(6, n = 402) = 6.885, p = 0.332
Survey incentive 1 2.106 0.147 Gift card Ref   
    $2 0.147 0.417 0.128–1.359
Survey length 2 2.628 0.269 Short Ref   
    Medium 0.819 1.111 0.452–2.733
    Long 0.233 0.621 0.284–1.358
Follow-up waves 2 1.735 0.420 0 Ref   
    2 0.366 1.595 0.581–4.384
    3 0.811 1.130 0.414–3.090
Field study incentive 1 0.001 0.971 150 Ref   
    200 0.971 1.011 0.550–1.861
Model 2
χ2(11, n = 402) = 20.832, p = 0.035
Survey incentive 1 2.095 0.148 Gift card Ref   
    $2 0.148 0.408 0.121–1.373
Survey length 2 2.854 0.240 Short Ref   
    Medium 0.753 1.158 0.463–2.899
    Long 0.234 0.615 0.277–1.369
Follow-up waves 2 1.564 0.457 0 Ref   
    2 0.422 1.529 0.543–4.310
    3 0.876 1.086 0.388–3.038
Field study incentive 1 0.010 0.921 150 Ref   
    200 0.921 0.969 0.519–1.808
Noise exposure category 4 10.830 0.029 < 40 Ref   
    40–45 0.311 0.721 0.383–1.358
    45–50 0.150 1.619 0.841–3.118
    50–55 0.072 1.775 0.949–3.318
    > 55 0.171 1.558 0.826–2.940
Direction 1 2.049 0.152 West    
    East 0.152 0.738 0.487–1.119
Model 3
χ2(17, n = 359) = 63.308, p < 0.0001
Survey incentive 1 3.719 0.054 Gift card Ref   
    $2 0.054 0.245 0.059–1.023
Survey length 2 1.659 0.436 Short Ref   
    Medium 0.873 1.086 0.396–2.973
    Long 0.330 0.647 0.270–1.553
Follow-up waves 2 1.461 0.482 0 Ref   
    2 0.228 2.153 0.619–7.489
    3 0.332 1.851 0.534–6.421
Field study incentive 1 0.164 0.685 150 Ref   
    200 0.685 1.160 0.565–2.381
Noise exposure category 4 8.904 0.064 < 40 Ref   
    40–45 0.803 0.909 0.430–1.924
    45–50 0.114 1.846 0.863–3.949
    50–55 0.029 2.304 1.088–4.875
    > 55 0.132 1.768 0.842–3.713
Direction 1 0.642 0.423 West Ref   
    East 0. 423 0.823 0.511–1.326
Sex 1 0.961 0.327 Female Ref   
    Male 0. 327 0.774 0.464–1.202
Age category 5 33.150 < 0.0001 < 30 Ref   
    30–39 0.073 0.140 0.016–1.202
    40–49 0.029 0.094 0.011–0.781
    50–59 0.010 0.065 0.008–0.525
    60–69 0.001 0.032 0.004–0.257
    ≥70 < 0.001 0.022 0.003–0.183
  1. All analyses excluded surveys that could not be delivered for any reason
  2. df Degrees of Freedom, OR Odds Ratio, CI Confidence Interval, Ref Reference category
  3. Statistically significant (p < 0.05) results are indicated with bold typeface. Results of borderline statistical significance (p = 0.05–0.1) are indicated with italic typeface