About the Authors

Nandi Siegfried

Roles Conceptualization, Data curation, Formal analysis, Methodology, Project administration, Software, Supervision, Writing – original draft, Writing – review & editing

Nandi.siegfried@mrc.ac.za

Affiliation Alcohol, Tobacco and Other Drug Research Unit, South African Medical Research Council, Tygerberg, South Africa

Charles Parry

Roles Conceptualization, Data curation, Formal analysis, Resources, Writing – review & editing

Affiliation Alcohol, Tobacco and Other Drug Research Unit, South African Medical Research Council, Tygerberg, South Africa

Competing Interests

We have read the journal's policy and the authors of this manuscript have the following competing interests: In 2017 and 2018, Nandi Siegfried worked as a consultant providing methodological support to the United Nations Office on Drugs and Crime and World Health Organization in the 2nd revision and update of the International Standards on Drug Use Prevention (see http://www.unodc.org/documents/prevention/standards_180412.pdf). Charles Parry is a board member of the Global Alcohol Policy Alliance. In 2016 he served as a consultant to the South African Western Cape Provincial Government in preparing a Green Paper on alcohol harms reduction. This does not alter our adherence to PLOS ONE policies on sharing data and materials.