Social desirability bias has been documented in self-reported diet as well as in voting behavior, but not in regards to sweetened beverage consumption or sweetened beverage taxes. We find evidence that respondents in a mixed-mode opinion survey exhibit social desirability bias in both reported sweetened beverage consumption and beliefs about the health and economic benefits of sweetened beverage taxes. We do so in a study of 1704 adults residing in Seattle, Minneapolis, and the D.C. metro area. Phone respondents in our survey under-report sweetened beverage consumption by 0.63 beverages per week relative to web respondents (average web respondent consumption is 3.55 beverages per week). They also over-report their beliefs about the positive health and economic impacts of sweetened beverage taxes by 0.54 points in an 18-point index (average web respondent index score is 2.79). These differences are measured after we control for selection into survey mode by using matching methods, and we interpret them as occurring due to social desirability bias. In contrast to these findings, there is no modal difference in respondents’ stated approval of sweetened beverage taxes, and so we conclude that this question is not subject to social desirability bias.

在自我报告的饮食和投票行为中已经记录了社会期望偏差，但在加糖饮料消费或加糖饮料税方面没有记录。我们发现有证据表明，混合模式意见调查中的受访者在报告的含糖饮料消费量和对含糖饮料税的健康和经济效益的看法方面都表现出社会期望偏差。我们在一项对居住在西雅图、明尼阿波利斯和华盛顿都会区的 1704 名成年人的研究中这样做了。与网络受访者相比，我们调查中的电话受访者每周少报 0.63 杯含糖饮料消费量（网络受访者平均每周消费 3.55 杯饮料）。他们还将他们对含糖饮料税对健康和经济的积极影响的看法高估了 0。18 分指数中的 54 分（平均网络受访者指数得分为 2.79）。这些差异是在我们使用匹配方法控制选择进入调查模式后测量的，我们将它们解释为由于社会期望偏差而发生。与这些调查结果相反，受访者对含糖饮料税的表示同意没有模态差异，因此我们得出结论，这个问题不受社会期望偏差的影响。