Lower-income children in Seattle are drinking less pop than before a soda tax was established, but so are their peers outside the city, according to a new report based on surveys with kids.

Seattle’s tax of 1.75 cents-per-fluid ounce on sugar-sweetened beverages took effect in January 2018. The tax is charged to beverage distributors. But the distributors can pass the tax on to stores and the stores can pass the tax on to consumers.

Proponents said they hoped the tax would reduce consumption of unhealthful drinks, particularly among lower-income children, and raise money for healthful food and education programs.

In the year after the tax took effect, lower-income Seattle kids surveyed by the University of Washington and the Seattle Children’s Research Institute reduced their consumption of taxed beverages by 3.3 ounces a day, according to the report released Wednesday.

Meanwhile, lower-income children surveyed in “comparison-area” cities without soda taxes, including Renton, Federal Way, Kent, Auburn and other South King County cities, reduced their consumption by 3.9 ounces a day.

The researchers surveyed the kids before Seattle’s tax took effect, six months later and 12 months later. They surveyed 127 children in Seattle and 188 in the comparison area, and their work was funded by the city. The children surveyed ranged from ages 7-17. The researchers had parents report consumption for kids under 12.


The percentage of lower-income children consuming a large amount of sugar-sweetened beverages declined, as well. Before the tax took effect, 30% of Seattle kids surveyed were drinking at least 8 ounces a day. A year later, only 20% were. In the comparison area, the measure dropped from 29% to 14%.

Consumption of soda pop declined most among Seattle children, while consumption of fruit-flavored beverages with sugar declined most among comparison-area kids. Consumption of non-sugar beverages, including water, also decreased among the children surveyed: 11.1% among the Seattle kids and 6.8% among the kids in the comparison area.

“As expected, lower-income children and parents living in Seattle who were part of our sample reduced sugary beverage consumption,” Wednesday’s report says.

“Unexpectedly, the reductions observed among Seattle families were similar to reductions observed among comparison area families over the one-year period.”

The result was unexpected because prices of sugary-sweetened beverages increased more in Seattle than in the comparison area, according to store and restaurant surveys, the report says.

The researchers collected price information from 386 stores and restaurants in Seattle and in comparison area before Seattle’s tax was implemented, six months and 12 months later.


The average price increase for sugary-sweetened beverages was 1.94 cents per ounce in Seattle and .26 cents per ounce in the comparison area, according to the surveys. Increases at Seattle stores near the city’s borders were lower than at stores elsewhere in the city.

So why did lower-income kids outside Seattle reduce their consumption even more than kids in Seattle?

“These findings could be the result of general norms and trends in sugary beverage consumption, limitations in our measurement of beverage consumption or other unknown factors affecting beverage consumption among lower-income families in our region,” Wednesday’s report says.

Earlier this year, a peer-reviewed study by University of Illinois at Chicago researchers said sales of sugary-sweetened beverages at stores in Seattle had dropped about 30.5%, while sales in Portland, which has no soda tax, had declined 10.5%.

Correction: An earlier version of this story misstated price increases for sugary beverages. The average price increase in the comparison area was .26 cents per ounce, according to the surveys, not 26 cents.