Effects of a responsible retailing mystery shop intervention on age verification by servers and clerks in alcohol outlets: A cluster randomised cross‐over trial

Clerks and servers at alcohol establishments often fail to verify age. Using mystery shoppers to provide performance feedback is one approach to improving age verification. Few controlled studies have evaluated mystery shop interventions. This paper reports on a cluster randomised cross-over trial of a mystery shop intervention in 16 communities in four US states.The intervention comprised monthly mystery shops after which clerks and servers...