A study from the National Center for Policy Analysis claims that a ban on plastic bags used by grocers and retailers can negatively impact sales in the ban area and increase sales among stores just outside the bag ban region.
The NCPA surveyed store managers in Los Angeles County, where a ban of thin-film bags took effect in July 2011. The group conducted a survey of 80 large stores such as supermarkets and variety shops affected by the ban.
Additionally, each large store in unincorporated Los Angeles County was matched with one or two other stores within two miles and also in an incorporated area. The stores were matched in order to compare the effect of any displacement of commerce due to the ban.
During a one-year period, before and after the ban, the majority of stores surveyed in areas with a ban reported an overall average sales decline of nearly 6%. While the majority of respondents surveyed in areas without a ban reported an overall average sales growth of 9%.