BACKGROUND:

Digital research methods have become useful tools in the study of hidden populations. Large samples are often obtained, but their external validity can be unclear. This paper compares an online purposive sample of Australian cannabis growers with a matched sub-sample accessed from a general population survey.

METHODS:

We compared the demographic and drug use characteristics of recent cannabis users who report recent cannabis cultivation from a probability (National Drug Strategy Household Survey, n=100) and purposive online sample (Global Cannabis Cultivation Research Consortium, n=327) using nonparametric (bootstrap) and meta-analysis techniques.

RESULTS:

The samples were not statistically significantly different by age, indigenous status, employment, completion of any educational qualification, living alone or with partner, daily cannabis use and recent other illicit drug use. The purposive online sample was more likely to report being male, residing in a regional/remote area and completion of a university qualification, while the probability sample was more likely to report first using cannabis under the age of 16 years and living with children.

CONCLUSION:

While our sample cannot be understood as representative, these findings provide greater confidence in our purposive sampling methodology that uses a wide range of internet and traditional recruitment sources.
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