Table 4. Effects of sugary drink warnings versus control: Mean weighted effect sizes (d with Hedges’s correction) and heterogeneity statistics (k = 23 studies), primary analyses.

Outcome	N	k	d (95% CI)	Q	p	I2
Behavior
Purchases of sugary drinks (primary outcome)	1,407	4	−0.17 (−0.30, −0.04)	4.30	0.231	16.61
Calories purchased from beverages	2,338	3	−0.16 (−0.24, −0.07)	1.23	0.540	0.01
Grams of sugar purchased from beverages	1,938	2	−0.11 (−0.21, −0.01)	0.00	0.949	0.00
Attention and noticing
Noticed nutrition or trial labels	1,840	2	0.83 (0.54, 1.12)	6.36	0.012	84.29
Warning reactions
Negative emotional reactions	3,594	4	0.69 (0.25, 1.13)	137.52	<0.001	97.39
Thinking about the health effects of sugary drinks	2,543	4	0.65 (0.29, 1.01)	41.54	<0.001	93.69
Attitudes and beliefs about sugary drinks
Healthfulness perceptions	6,947	9	−0.22 (−0.27, −0.17)	8.15	0.419	1.68
Positive outcome expectancies	4,583	2	−0.26 (−0.34, −0.17)	3.93	0.047	74.55
Positive product attitudes	5,969	6	−0.54 (−1.43, 0.35)	223.34	<0.001	99.74
Perceived disease likelihood	7,072	6	0.15 (0.06, 0.24)	39.46	<0.001	83.02
Perceptions of amount of added sugar	4,983	3	0.25 (−0.05, 0.55)	38.55	<0.001	95.37
Policy support	2,132	2	0.19 (−0.14, 0.51)	13.86	<0.001	92.79
Intentions and hypothetical choices
Hypothetical purchases of sugary drinks	7,681	6	−0.32 (−0.44, −0.21)	14.70	0.012	78.69
Purchase or consumption intentions	7,118	8	−0.30 (−0.44, −0.15)	40.85	<0.001	89.36
Hypothetical coupon selection—sugary drinks	4,583	2	−0.31 (−0.37, −0.25)	0.00	0.972	0.04
Hypothetical coupon selection—non-sugary drinks	4,583	2	−0.02 (−0.21, 0.17)	9.57	0.002	89.55
Hypothetical total expenditure on beverages	1,189	2	−0.08 (−0.21, 0.06)	0.46	0.495	0.00

N, number of participants; k, number of studies/effect sizes; d, corrected standardized mean difference (pooled effect size). Effect sizes in bold are statistically significant at p < 0.05.