Abstract

Purpose Sexual-assault crimes, primarily perpetrated by males against female victims, impose a substantial burden on societies worldwide, especially on youth. Given that approximately half of all sexual assaults involve alcohol consumption by the perpetrator or victim, it is reasonable to expect that minimum legal drinking age (MLDA) restrictions might have an effect on sexual-assault patterns. Canadian MLDA laws are 18 years in Quebec, Alberta, and Manitoba (MLDA-18), and 19 years in the rest of the country (MLDA-19). The present study assesses whether MLDA laws might have an impact on sexual-assault crimes.

Methods A regression-discontinuity design was applied to sexual-assault crime data (n = 12,980 incidents) from the national Uniform Crime Reporting survey 2009–2013, a population-level registry of all police-reported crimes in Canada. Uniform Crime Reporting data does not include an explicit alcohol involvement indicator.

Results Nationally, in comparison to males slightly younger than the MLDA, those just older had significant and immediate increases in sexual-assault perpetration of 31.9% (95% confidence interval: 8.7%–54.5%, p = .007). In MLDA-19 provinces, there was an immediate post-MLDA increase of 56.0% (95% confidence interval: 18.9%–90.8%, p = .004) in sexual-assault crimes by males just older than 19 years, whereas in MLDA-18 provinces no significant effect was found. For females, there was no evidence of MLDA effects on sexual-assault crimes.