Aim In February 2000, a trial started with Saturday opening of alcohol retail shops in certain parts of Sweden (phase I), and in July 2001, Saturday opening was extended to the whole country (phase II). The aim of this study is to assess the impact of phase II, and to probe previous results regarding phase I.
Design Prior to February 2000, all alcohol monopoly outlets were closed on Saturdays. After this date, stores in an experimental area (six counties) were open on Saturdays. In the control area (seven counties) the shops remained closed. To prevent biases due to trade leakage, the experimental and control areas were separated by a buffer area (seven counties). Because continuous evaluations of the trial did not reveal any negative consequences, the Saturday opening was implemented in the whole of Sweden after 17 months.
Data and methods The outcome measures included alcohol sales and indicators of assaults and drunk driving. The pre-intervention period covered the time period January 1995-January 2000, phase I of the post-intervention period February 2000–June 2001 (17 months), and phase II July 2001–July 2002 (13 months). The effects of the two phases were estimated through analyses of monthly data (auto-regressive integrated moving-average (ARIMA) modelling) depicting how sales and harm rates evolved in the experimental area compared to the control area during phase I as well as during phase II.
Results The analysis uncovered a statistically significant increase in alcohol sales of 3.7% during phase I, and about the same increase during phase II (3.6%). There were no significant changes in any of the assault indicators, neither during phase I nor during phase II. There was a statistically significant increase in drunk driving (12%) during phase I, but no change during phase II. The analyses suggested that the increase during phase I was mainly due to a change in the surveillance strategy of the police.
Conclusions The results lend support to the public health perspective in that the increased accessibility to alcohol rendered by Saturday opening also seems to have increased consumption. On the other hand, we could not detect any increase in alcohol-related harm. The question of whether this may be due to insufficient statistical power is discussed, together with some other methodological complications that were highlighted by the study.