The news is full of widely (and wildly) varying estimates of the scale and scope of human trafficking. This is partly because vulnerable individuals are often hidden and are therefore hard to count.

Respondent-driven sampling is a form of snowball sampling which allows researchers to make estimates about hidden population such as the three groups at highest risk for HIV/AIDS: injection drug users ...

ABSTRACT: Agroforestry Systems (AFS) in Cameroon have considerable socio-economic potential and their composition is essentially determined by the type of producers and their strategies. This study ...