Perceived effectiveness of pictorial warnings: mean weighted effect sizes (d) and heterogeneity statistics
| N | k | d | 95% CI | p Value | Q | p Value | I2 | |
|---|---|---|---|---|---|---|---|---|
| Perceived effectiveness of warning to… | ||||||||
| Motivate me/others to not start smoking | 3946 | 4 | 1.03 | (0.30 to 1.75) | 0.006 | 251 | 0.001 | 99 |
| Motivate me to cut down on smoking | 450 | 2 | 0.41 | (0.07 to 0.75) | 0.02 | 3 | 0.09 | 64 |
| Motivate me to quit smoking | 5986 | 10 | 0.79 | (0.41 to 1.18) | 0.001 | 356 | 0.001 | 97 |
| Motivate others to quit smoking | 3667 | 5 | 1.09 | (0.39 to 1.80) | 0.002 | 238 | 0.001 | 98 |
| Motivate me/others to not smoke (composite) | 3807 | 3 | 0.24 | (0.18 to 0.31) | 0.001 | 2 | 0.47 | 0 |
| Be generally effective (no referent) | 3405 | 4 | 1.00 | (0.20 to 1.80) | 0.01 | 344 | 0.001 | 99 |
| Be effective for me/others (scale) | 4512 | 4 | 0.52 | (0.07 to 0.97) | 0.02 | 63 | 0.001 | 95 |
| Deter giving cigarettes as gift | 3504 | 2 | 1.64 | (1.37 to 1.91) | 0.001 | 13 | 0.001 | 92 |
n, number of participants; k, number of effect sizes; d, standardised mean difference (pooled effect size).