Table 1.
Second-order meta-analytical results
| Meta-analyses m | Meta-analytic effect sizes n | Primary studies k | Overall grand mean d | 95% CI lower limit | 95% CI upper limit | |
|---|---|---|---|---|---|---|
| Overall | ||||||
| Averaged over meta-analyses | 10 | 10 | 1,178 | 0.310 | 0.302 | 0.320 |
| Averaged over subgroup effect size | 10 | 38 | 1,041 | 0.303 | 0.292 | 0.313 |
| Unique effect size | 10 | 10 | 663 | 0.310 | 0.280 | 0.340 |
| Interventions | ||||||
| Appeals | 1 | 1 | 10 | 0.279 | 0.279 | 0.279 |
| Commitment | 3 | 3 | 67 | 0.272 | 0.261 | 0.284 |
| Education | 5 | 5 | 121 | 0.087 | 0.076 | 0.099 |
| Feedback | 4 | 4 | 120 | 0.159 | 0.149 | 0.169 |
| Financial incentives | 4 | 6 | 73 | 0.317 | 0.296 | 0.338 |
| Social comparison | 5 | 9 | 199 | 0.370 | 0.351 | 0.389 |
| Outcomes | ||||||
| Conservation | 6 | 13 | 404 | 0.254 | 0.239 | 0.270 |
| Consumption | 2 | 3 | 18 | 0.197 | 0.178 | 0.217 |
| Littering | 1 | 1 | 22 | 0.519 | 0.519 | 0.519 |
| Recycling | 4 | 9 | 103 | 0.273 | 0.236 | 0.309 |
| Transportation | 4 | 5 | 57 | 0.079 | 0.064 | 0.093 |
Note. All statistics in Table 1 are second-order meta-analytic estimates without publication bias adjustments. The number of unique included primary studies is lower than reported here due to study overlap, see main text for more details. 1) number of meta-analyses; 2) number of meta-analytical effect sizes; 3) number of primary studies; 4) second-order, grand mean standardized difference estimate; 5) lower limit of the 95% confidence interval (CI); 6) upper limit of the 95% CI. See Appendix for 7) observed variance across first-order mean standardized difference estimates; 8) expected second-order sampling error variance; 9) estimated true variance across first-order mean standardized difference estimates (expected sampling error variance removed).