Table 3.
Weekly spending ($) among 351 shoppers participating in a randomized controlled trial of a double value incentive on fruits and vegetables in a Maine supermarket, stratified by SNAP participation. Values are mean (SE) unless indicated otherwise.
| Intervention | Intervention/Redeemed Incentives | Control | Difference-in-Difference (Intervention vs Control) Mean (95% CI) | % change | P-value | Difference-in-Difference
(Intervention: Redeemed Incentives vs Control) Mean (95% CI) |
% change | P-value | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Baseline | Intervention | Baseline | Intevention | Baseline | Intervention | |||||||
| SNAP | ||||||||||||
| Total fruits and vegetables | 5.23 (1.40) | 7.09 (1.34) | 7.77 (2.05) | 12.38 (1.95) | 5.74 (1.39) | 5.22 (1.33) | 2.37 (-0.01, 4.75) | 45.3 | 0.05 | 5.14 (1.93, 8.34) | 66.2 | <0.01 |
| Fresh fruits and vegetables | 4.79 (1.35) | 6.74 (1.29) | 7.13 (1.97) | 11.87 (1.88) | 5.45 (1.33) | 4.85 (1.27) | 2.55 (0.26, 4.84) | 53.2 | 0.03 | 5.34 (2.26, 8.41) | 74.9 | <0.001 |
| Non SNAP | ||||||||||||
| Total fruits and vegetables | 14.00 (1.35) | 15.79 (1.31) | 16.63 (1.61) | 20.72 (1.55) | 15.72 (1.43) | 15.94 (1.39) | 1.57 (-0.35, 3.49) | 11.2 | 0.11 | 3.88 (1.67, 6.08) | 23.3 | <0.001 |
| Fresh fruits and vegetables | 12.93 (1.27) | 14.78 (1.23) | 15.34 (1.52) | 19.37 (1.47) | 14.62 (1.35) | 14.79 (1.31) | 1.68 (-0.14, 3.51) | 13.0 | 0.07 | 3.86 (1.76, 5.95) | 25.2 | <0.001 |
Values reflect spending before transaction-level discounts were applied. Holiday weeks of Thanksgiving (11/22–11/28) and Christmas (12/20–12/26) were excluded. “Intervention/redeemed-incentives” is defined as those shoppers assigned to incentives who made a transaction during the intervention period in which the double value incentive was redeemed at least once (n=123). Supplemental Nutrition Assistance Program (SNAP) is defined as shoppers who reported participating in SNAP or used SNAP during the study period. Shoppers missing SNAP were excluded (n=3). Statistical tests are two-tailed t-tests from regressions with random intercepts to account for clustering of observations within individuals. All models are unadjusted for demographics.