Impact on alcohol purchasing of a ban on multi-buy promotions: a quasi-experimental evaluation comparing Scotland with England and Wales

AIMS: To evaluate the impact of the 2011 Scottish ban on multi-buy promotions of alcohol in retail stores. DESIGN AND SETTING: Difference-in-differences analysis was used to estimate the impact of the ban on the volume of alcohol purchased by Scottish households, compared with those in England and Wales, between January 2010 and June 2012. PARTICIPANTS: A total of 22 356 households in Scotland, England and Wales. MEASUREMENTS: Records of alcohol purchasing from each of four categories (beer and cider, wine, spirits and flavoured alcoholic beverages), as well as total volume of pure alcohol purchased. FINDINGS: Controlling for general time trends and household heterogeneity, there was no significant effect of the multi-buy ban in Scotland on volume of alcohol purchased either for the whole population or for individual socio-economic groups. There was also no significant effect on those who were large pre-ban purchasers of alcohol. Most multi-buys were for beer and cider or for wine. The frequency of shopping trips involving beer and cider purchases increased by 9.2% following the ban (