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Using Internet-based surveys to reach hidden populations: case of nonabusive illicit drug users.

OBJECTIVE
To examine the potential of surveys delivered via the World Wide Web (WWW) as a method for reaching hidden populations such as that of nonabusive users of illicit drugs.


METHODS
Past and current approaches to collecting data from hidden populations were reviewed.


RESULTS
A number of approaches have been used in the past efforts to reach drug users but the use of the WWW has produced the largest sample of successful illicit drug users ever surveyed.


CONCLUSION
Further application of this approach (WWW) is recommended when hidden populations are surveyed.