Table 4

Estimated percentage change in calories (kcal) purchased due to incentives across the household income distribution

Low incomeMiddle incomeHigh incomeχ2-test of equality
Product category: biscuits
 10% Price reduction4.2*** (4.0 to 4.3)4.4*** (4.2 to 4.5)4.5*** (4.3 to 4.8)6.623**
 Any price promo.35.4*** (33.4 to 37.4)39.1*** (37.2 to 41.0)36.1*** (33.4 to 38.8)7.678**
 Any volume promo.70.7*** (67.8 to 73.5)73.7*** (71.2 to 76.1)75.2*** (72.1 to 78.4)4.749*
 Observations78 00979 43242 441
 Households12261351754
Product category: crisps
 10% Price reduction8.7*** (8.3 to 9.2)8.7*** (8.3 to 9.2)8.9*** (8.4 to 9.5)0.400
 Any price promo.8.3*** (6.0 to 10.6)6.9*** (4.7 to 9.0)7.8*** (5.2 to 10.4)0.829
 Any volume promo.50.4*** (46.7 to 54.2)52.9*** (49.9 to 55.9)53.8*** (49.9 to 57.8)1.656
 Observations48 28155 09132 014
 Households12111338751
Product category: savoury snacks
 10% Price reduction6.2*** (5.9 to 6.6)6.5*** (6.2 to 6.9)6.4*** (6.0 to 6.7)1.889
 Any price promo.25.2*** (22.8 to 27.6)27.3*** (24.9 to 29.7)26.6*** (23.8 to 29.5)1.474
 Any volume promo.76.2*** (72.9 to 79.5)77.5*** (74.2 to 80.8)79.8*** (76.0 to 83.6)1.941
 Observations40 19047 86830 578
 Households12121342745
  • 95% CI in brackets *p < 0.10, **p < 0.05, ***p < 0.01.

  • Number of observations within categories varies based on the number of purchases per household.

  • All models include age of main shopper, age2 of main shopper, household size, time in panel (years), time since last purchase (weeks), and year dummies (full results available in online supplemental appendix).