Table 3.
Nudge effectiveness and modifying effects on fruit and vegetable purchases, in the longitudinal analysis (n = 638)1
| β | 95%CI | p-value | |
|---|---|---|---|
| Crude intervention group main effect | 0.00 | -0.04, 0.04 | 0.94 |
| Adjusted intervention group main effect2 | 0.00 | -0.03, 0.09 | 0.91 |
| Nudge interventions x higher educational attainment2 | -0.06 | -0.40, 0.02 | 0.20 |
| Nudge interventions x females2,3 | 0.13 | -0.00, 0.61 | 0.09 |
| Nudge interventions x older adults2,3 | -0.05 | -0.39, 0.02 | 0.25 |
1Main within- and between group nudge effectiveness and modifying effects of group by educational attainment, sex, and age, on the percentage of fruit and vegetables purchased, based on the longitudinal analysis. Analyses were based on a three-level linear mixed-effects model, with group as independent variable and the square root of the percentage of fruit and vegetable purchases as the dependent variable. Further fixed effects were time (categorical) and the baseline measurement of percentage of fruit and vegetable purchases. Random intercepts were included for trials, grocery stores, and participants. Results reflect back-transformed means from the square root transformations
2Adjusted for educational attainment, sex, age, and the number of persons purchased groceries for
3Based on n = 541 due to absence of males and older adults in the data by Vogel et al