Salgado Juan Carlos, Ng Shu Wen
Department of Health Policy and Management, Gillings School of Global Public Health, the University of North Carolina at Chapel Hill, NC, United States.
Carolina Population Center and Department of Nutrition, Gillings School of Global Public Health, the University of North Carolina at Chapel Hill, NC, United States.
Food Policy. 2019 Dec;89. doi: 10.1016/j.foodpol.2019.101783. Epub 2019 Oct 26.
To address the high prevalence of overweight and obesity in Mexico, an eight percent ad valorem excise tax on non-essential energy-dense foods came into effect on 1 January 2014. This paper estimates price changes after the tax implementation among the top four food categories and by leading vs. non-leading firms using purchase information from over 6000 urban households in the 2012-2015 Nielsen Mexico Consumer Panel. We create product-city-month specific prices that correct for potential biases associated with household and retailer characteristics. Using these corrected prices, we conduct before and after quasi-experimental analyses and find that price increases were larger than eight percent for cookies but were less than eight percent for ready-to-eat cereals, salty snacks, and pre-packaged sweet bread. For the latter food group, event-study analyses on the gradual price change over time suggest that price changes might be the result of an increasing price trend rather than the tax implementation. Firm-level analyses mostly show that price increases by the leading firms were larger than the overall increase at the food market level, helping explain variability in post-tax declines in food purchases as reported in other research. We also find that price changes are generally underestimated when we do not correct prices for biases associated with households and retailers. These results improve our understanding of the mechanisms behind heterogeneous changes in purchases after the tax implementation. Additionally, these results can assist policymakers when designing or improving taxes on non-essential energy-dense foods at a time when these policy options are high on the agenda in many places.
为应对墨西哥超重和肥胖的高流行率，对非必需的高能量食品征收8%的从价消费税于2014年1月1日生效。本文利用2012 - 2015年尼尔森墨西哥消费者面板中6000多个城市家庭的购买信息，估计了税收实施后四大食品类别以及领先企业与非领先企业之间的价格变化。我们创建了针对产品、城市和月份的特定价格，以纠正与家庭和零售商特征相关的潜在偏差。使用这些校正后的价格，我们进行了前后准实验分析，发现饼干的价格涨幅超过8%，但即食谷物、咸味小吃和预包装甜面包的涨幅不到8%。对于后一类食品，对随时间逐渐变化的价格进行的事件研究分析表明，价格变化可能是价格上涨趋势增加的结果，而非税收实施的结果。企业层面的分析大多表明，领先企业的价格涨幅大于食品市场层面的总体涨幅，这有助于解释其他研究中报告的税后食品购买量下降的差异。我们还发现，当我们不对与家庭和零售商相关的偏差进行价格校正时，价格变化通常会被低估。这些结果增进了我们对税收实施后购买量异质性变化背后机制的理解。此外，在许多地方这些政策选择被提上议程之际，这些结果可以在政策制定者设计或改进对非必需高能量食品的税收时提供帮助。
