The impact of shelf tags with Nutri-Score on consumer purchases: a difference-in-difference analysis of a natural experiment in supermarkets of a major retailer in Belgium

Table 3 Impact of ESL on proportion of total weekly food sales for Nutri-Score A, B, C, D, E products, unadjusted and adjusted for region, cluster, week of the year and total non-food sales

	% (SE) of total food sales
	control		intervention		p	diff-in-diff
Nutri-Score	before	after	before	after	baseline diff¹	coeff² (SE)	p
	Unadjusted
A	32.9 ± 0.5	32.3 ± 0.6	33.7 ± 0.3	33.0 ± 0.4	0.173	−0.05 ± 0.52	0.928
B	13.5 ± 0.1	13.8 ± 0.2	13.4 ± 0.1	13.7 ± 0.1	0.370	0.08 ± 0.21	0.718
C	13.9 ± 0.1	13.8 ± 0.1	13.8 ± 0.1	13.7 ± 0.1	0.834	−0.06 ± 0.21	0.776
D	20.8 ± 0.3	21.4 ± 0.3	20.4 ± 0.2	21.1 ± 0.2	0.258	0.09 ± 0.32	0.786
E	10.5 ± 0.2	10.6 ± 0.2	10.3 ± 0.1	10.5 ± 0.1	0.262	0.05 ± 0.16	0.773
	Adjusted for region, cluster and total non-food sales
A	33.1 ± 0.4	32.8 ± 0.5	34.0 ± 0.3	33.8 ± 0.4	0.058	0.11 ± 0.52	0.832
B	13.4 ± 0.1	13.9 ± 0.2	13.5 ± 0.1	14.1 ± 0.2	0.884	0.16 ± 0.21	0.450
C	13.8 ± 0.1	13.8 ± 0.1	13.8 ± 0.1	13.8 ± 0.1	0.746	−0.03 ± 0.21	0.898
D	20.9 ± 0.1	21.6 ± 0.2	20.6 ± 0.1	21.5 ± 0.2	0.132	0.16 ± 0.31	0.615
E	10.3 ± 0.1	10.5 ± 0.1	10.3 ± 0.1	10.5 ± 0.1	0.597	0.07 ± 0.16	0.669
	Adjusted for region, cluster, total non-food sales and week of the year
A	32.9 ± 0.5	33.4 ± 1.0	33.3 ± 0.4	33.7 ± 0.9	0.316	−0.09 ± 0.06	0.176
B	13.7 ± 0.2	13.1 ± 0.6	13.6 ± 0.1	13.1 ± 0.6	0.521	0.11 ± 0.04	0.007
C	13.7 ± 0.2	13.7 ± 0.4	13.8 ± 0.2	13.6 ± 0.4	0.856	−0.06 ± 0.03	0.026
D	21.0 ± 0.2	20.9 ± 0.5	20.8 ± 0.2	20.8 ± 0.5	0.144	0.12 ± 0.04	0.002
E	10.4 ± 0.2	10.3 ± 0.5	10.3 ± 0.2	10.3 ± 0.5	0.546	0.04 ± 0.03	0.265

¹ p-value for mean difference in outcome between intervention and control groups prior to the intervention (existing baseline differences)
² Difference in difference estimator. It shows whether the expected mean change in % total sales for Nutri-Score A,B,C,D,E from before to after was different between control and intervention stores

ISSN: 1479-5868