Minimum Legal Age of Tobacco Sales Law as a Commitment Mechanism: A Regression Discontinuity Design

OBJECTIVES: The economic rationale for minimum legal age (MLA) of sale restrictions is founded in the commitment-value they provide. Smokers impose negative externalities upon themselves in the form of damage to health and loss of life expectancy. Additionally, smoking initiation at an early age leads to smoking in later life and is associated with higher costs for public healthcare systems. In 2007 UK raised the MLA of tobacco sale from 16 to 18. Nevertheless, evidence suggests that the law is not properly implemented with 58% of youths under 18 reporting buying cigarettes from stores in 2008 and 38% in 2016. This study addresses the question whether access restriction laws succeed as a commitment mechanism to prevent individuals with low self-control from initiating into smoking at an early age.

METHODS: First, the immediate impact of the reform was tested on a sample of the British Household Panel Survey (BHPS) in terms of a reduction in propensity to smoke, applying a regression discontinuity framework and a narrow window of two years before and after the reform; next, the impacted cohort was followed into the future using data from Understanding Society to see whether the reduction in uptake was maintained throughout adulthood or if the policy only had a temporary “access” effect.

RESULTS: Intention to treat effect was a 11.3 percentage point reduction in propensity to smoke for individuals who could not legally buy cigarettes before the reform. Results from the second part of analysis were not statistically significant.

CONCLUSIONS: Increasing the MLA of tobacco sale produced a temporary effect of delaying smoking initiation. Access restriction laws are not a perfect commitment mechanism because of enforcement issues and availability of non-retail sources of tobacco. Consequently, the age restriction might be more effective if combined with legislation regulating possession of tobacco for those underage.