A few researchers have tried to answer this question, with mixed results. Alex Stevens at the University of Kent reanalyzed the data from a 2015 paper which claimed that liberal cannabis policies increase teen use. The data included a multi-year survey of over 170,000 people in 38 different countries. Such a large data set has many variables that can be analyzed. The analysis by Stevens only involves a few changes: it includes participants who did not list their number of siblings; it includes missing data from Sweden; it accounts for gender differences in cannabis use that may not be the same in every country. These methodological changes allow Stevens to analyze roughly 57,000 more participants than in the original study. Using these methods, the data do not support the notion that more liberal cannabis laws promotes teen use. This is not absolute proof that decriminalization, medical laws, or outright legalization will not affect teen use. But such fears are not well substantiated. Moreover, the converse — criminalizing drug use — is abjectly harmful for drug users.