Table 3

Effectiveness of pictorial warnings: mean weighted effect sizes (d) and heterogeneity statistics

Nkd95% CIp ValueQp ValueI2
Attention and recall
 Attention attracting18 37960.79(0.50 to 1.07)0.0013010.00198
 Attention duration16921.74(1.39 to 2.10)0.001<10.420
 Response time3867−0.03(−0.23 to 0.17)0.7720.920
 Recall/recognition of warning text15 0525−0.03(−0.06 to 0.02)0.2220.760
Warning reactions—cognitive, emotional and physiological
 Cognitive elaboration208231.70(0.85 to 2.55)0.0011050.00198
 Negative affective reactions16 906110.54(0.44 to 0.64)0.001440.00177
 Credibility20 22290.15(0.07 to 0.23)0.001350.00177
 Lower psychological reactance14 3244−0.50(−0.70 to −0.30)0.001610.00195
 Lower smoking cravings334720.08(0.01 to 0.16)0.03<10.680
 Aversiveness14 07430.58(0.42 to 0.75)0.001310.00193
 Negative pack/brand attitudes126070.79(0.50 to 1.07)0.001280.00178
 Negative smoking attitudes48940.55(0.28 to 0.83)0.00160.1151
 Perceived likelihood of harm14 46080.02(−0.04 to 0.07)0.65130.0648
 Self-efficacy to quit338520.01(−0.06 to 0.08)0.80<10.960
 Lower willingness to pay58020.26(0.02 to 0.50)0.0420.1747
 Intention to not start smoking501641.82(0.15 to 3.49)0.033360.00199
 Intention to quit smoking16 67180.54(0.29 to 0.79)0.0012560.00197
  • n, number of participants; k, number of effect sizes; d, standardised mean difference (pooled effect size).