Impact of a sugar-sweetened beverage tax two-year post-tax implementation in Seattle, Washington, United States

This study examines longer-run impacts of the Seattle, Washington, Sweetened Beverage Tax (SBT) on beverage prices, volume sold, and cross-border shopping. We use a difference-in-differences estimation approach, drawing on universal product code-level store scanner data on taxed and untaxed beverages one-year pre-tax and two-year post-tax with Portland, Oregon, as the comparison site. Two-year post-tax, prices of taxed beverages increased by 1.04 cents per ounce (59% tax pass-through rate). Volume sold of taxed beverages fell by 22%. Declines were larger for family-size (29%) compared to individual-size (10%) beverages; particularly for soda (36% decrease for family-size compared to no change for individual-size). We found no change in volume sold of taxed beverages in Seattle's 2-mile border area, suggesting no cross-border shopping. Overall, we found a sustained impact of the Seattle SBT two-year post-tax implementation suggesting that sugar-sweetened beverage taxes may yield permanent reductions in demand for sugary beverages and associated health harms.

Automated summary

This study found that the implementation of the Seattle Sweetened Beverage Tax may lead to an increase in prices and decrease in sales volume of taxed beverages; no cross-border shopping was found in the border area. The results suggest that sugar-sweetened beverage taxes may effectively reduce the demand for sugary beverages.