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Global Obesity Prevention Center

Systems-oriented Approach to Evaluating Local Sugar-sweetened Beverage Tax Ordinances


Principal Investigator: Kristine Madsen, MD, MPH




ssbCompelling evidence indicates that sugar-sweetened beverages (SSBs) promote unhealthy weight gain.  Due to the success of taxation in tobacco control, taxing SSBs has been proposed to reduce consumption while raising funds for obesity prevention.  Thus, the cities of San Francisco and Berkeley, CA placed on their November 2014 ballots measures to levy an SSB excise tax on beverage distributors. 

Ultimately, the measure passed in Berkeley but not San Francisco. The extent to which the excise tax may influence behavior hinges largely on the degree to which the tax is passed onto retail prices and how revenues are spent.  Additionally, simply having a tax on the ballot and the public discourse about the measure may influence behavior

sf studyLeveraging this natural experiment in the San Francisco Bay Area, this pilot study will examine the impact of an SSB excise tax on prices of SSBs and consumer habits and perceptions regarding SSBs. Additionally, through the window of news media and by using ethnographic content analyses, we will assess how the debates over taxing SSBs in Berkeley unfolded in local and national news coverage throughout the campaigns and immediately following the elections.



Baseline data collection:  Collection of pre-soda tax beverage prices and data on consumer habits and perceptions about sugar-sweetened beverages.

Baseline prices of top-selling sugar-sweetened, diet, and unsweetened beverages were collected from approximately 90 stores, and over 1,000 intercept surveys were conducted across Berkeley, San Francisco, and Oakland. Approximately 2,000 surveys were conducted among San Francisco school children. 

snapple   coke

Media component: Collection of news articles and other media coverage.

Assessed the volume of newspaper, blog and social media coverage of the Berkeley soda tax and conducted preliminary scans for key themes. 

Sample Presentation:

Sample Publication:

Additional Information:
To learn more, please email the Global Obesity Prevention Center at Johns Hopkins here.