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. Author manuscript; available in PMC: 2016 May 1.
Published in final edited form as: Tob Control. 2015 May 6;25(3):341–354. doi: 10.1136/tobaccocontrol-2014-051978

Table 4.

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).