The study compared beverage costs and sales in Philadelphia — following implementation of the 1.5 cents per ounce tax — with Baltimore, which has a similar demographic but doesn’t have the same sales tax. With the tax, beverages in Philadelphia jumped from 5.43 cents per ounce in 2016 to 6.24 cents in 2017. In Baltimore, beverages went up from 5.33 cents per ounce to just 5.50 cents.
While researchers found that sales of sugary beverages fell in Philadelphia after the tax, beverage sales in nearby towns and counties without the tax went up. That suggests people may have been traveling to get their soda at a reduced price. Adjusting for this shift, researchers found sales dropped 38% overall.
“We have tried, and failed, to curb sugary drink intake through education and individual choices alone,” Muth, who was lead author of the policy statement published in the journal Pediatrics, said at the time. “Just like policy changes were necessary and effective in reducing consumption of tobacco and alcohol, we need policy changes that will help reduce sugary drink consumption in children and adolescents.”
Unlike other communities with the tax, Philadelphia did not see an increase in sales of untaxed beverages such as bottled water. Researchers also found that people did not opt to swap their usual soda for liquid and powdered drink concentrates.
This study did not look into changes in beverage consumption or health outcomes associated with the tax.