Tag Archives: methodology

Rebuttal of the San Jose Bag Ban Results

English: Montage of San Jose, California pictures.
English: Montage of San Jose, California pictures. (Photo credit: Wikipedia)

In November of 2012, ten months after implementation of the San Jose Bag Ban, the city issued a report claiming success.  The memorandum contained an analysis of litter surveys and claimed a reduction of on-land plastic bag litter of 59%, 60% in creeks, and 89% in storm drains.  The latter figure is widely used by bag ban proponents as proof the law works.  However, problems with the underlying data as well as the methodology used indicate that these reduction figures are questionable.  Other factors such as a cost analysis was never done by the city nor were other less costly alternatives investigated.

In an article “San Jose Bag Ban Report Rebuttal” the authors respond to the claims of success in a stinging rebuttal.  The authors claim that the wrong parameter was measured, measurement methodology was unscientific and flawed, bag usage observations were not taken at a broad cross-section of stores, no cost/benefit analysis was conducted, and serious negative impacts were never addressed.

The authors present an analysis of plastic bag litter reduction calculations by the city as well as supply their own.  Also presented is a pre ban and post ban cost analysis of carryout bag use showing the cost increase that is incurred by consumers.