The relationship between sugar sweetened beverage (SSB) consumption and increased risk of obesity, diabetes, and heart disease is strong. In response, SSB taxes have been implemented in several U.S. cities, including Seattle. Pre-tax surveys of Seattle residents show that the majority favor the tax, but the recent experience of Chicago, where the tax was repealed by voters, suggests such policies are vulnerable. One reason polls may overestimate support for SSB taxes is social desirability bias in mixed mode surveys, a phenomenon where respondents are less willing to give their true opinions about socially sensitive subjects on the phone or in person than they are on the web. We show that response mode matters to questions about SSB consumption and approval of SSB taxes in a mixed mode survey of Seattle and two other cities. Consequently, we develop a method for controlling for mode effects in these surveys.
Presented in Session 5. Health & Mortality 1