The short-term impact of standardised packaging on smoking and snus use in Norway.

-We could not confirm or disconfirm whether standardised packaging is an effective tobacco control measure in a Norwegian context.-According to our analyses, standardized packaging may have effects on smoking prevalence and women's snus use, but is unlikely to reduce men's snus use.-The present results may reflect higher effectiveness of standardised packaging for products with stronger health warnings.-As the results varied according to samples and outcomes, the study underlines the importance of pre-registering future analyses on this topic.-Future confirmatory research should test models of gradual impact of standardised packaging.