1Nutritional Sciences Program,University of Washington,Nutritional Sciences Box 353410,305 Raitt Hall,Seattle,WA 98195,USA.
2Department of Epidemiology,University of Washington,Seattle,WA,USA.
Public Health Nutr. 2018 Jun;21(9):1762-1770. doi: 10.1017/S1368980017004037. Epub 2018 Feb 7.
To examine the impacts of Seattle's minimum wage ordinance on food prices by food processing category.
Supermarket food prices were collected for 106 items using a University of Washington Center for Public Health Nutrition market basket at affected and unaffected supermarket chain stores at three times: March 2015 (1-month pre-policy enactment), May 2015 (1-month post-policy enactment) and May 2016 (1-year post-policy enactment). Food items were categorized into four food processing groups, from minimally to ultra-processed. Data were analysed across time using a multilevel, linear difference-in-differences model at the store and price level stratified by level of food processing.
Six large supermarket chain stores located in Seattle ('intervention') affected by the policy and six same-chain but unaffected stores in King County ('control'), Washington, USA.
One hundred and six food and beverage items.
The largest change in average price by food item was +$US 0·53 for 'processed foods' in King County between 1-month post-policy and 1-year post-policy enactment (P < 0·01). The smallest change was $US 0·00 for 'unprocessed or minimally processed foods' in Seattle between 1-month post-policy and 1-year post-policy enactment (P = 0·94). No significant changes in averaged chain prices were observed across food processing level strata in Seattle v. King County stores at 1-month or 1-year post-policy enactment.
Supermarket food prices do not appear to be differentially impacted by Seattle's minimum wage ordinance by level of the food's processing. These results suggest that the early implementation of a city-level minimum wage policy does not alter supermarket food prices by level of food processing.
按食品加工类别考察西雅图最低工资条例对食品价格的影响。
在三个时间点使用华盛顿大学公共卫生营养中心的市场篮子，在受影响和不受影响的超市连锁店收集 106 种食品的超市食品价格：2015 年 3 月（政策颁布前 1 个月）、2015 年 5 月（政策颁布后 1 个月）和 2016 年 5 月（政策颁布后 1 年）。将食品项目分为四类食品加工组，从最低限度到超加工。使用多层次线性差异差异模型在商店和价格水平上对数据进行分析，按食品加工水平进行分层。
位于美国华盛顿州西雅图的六家大型连锁超市（“干预”）受到该政策的影响，金县（“对照”）的六家相同连锁但不受影响的商店也受到该政策的影响。
106 种食品和饮料。
在金县，政策颁布后 1 个月至 1 年期间，食品项目的平均价格变化最大，加工食品每单位增加 0.53 美元（P<0.01）。西雅图未加工或最低限度加工食品的价格变化最小，为 0.00 美元（P=0.94）。在西雅图和金县的商店中，在政策颁布后 1 个月或 1 年，在食品加工水平分层中，没有观察到连锁店平均价格的显著变化。
西雅图最低工资条例似乎不会按食品加工水平对超市食品价格产生不同的影响。这些结果表明，城市一级最低工资政策的早期实施不会改变按食品加工水平划分的超市食品价格。
