A case against social networks as the only means for recruitment in scientific studies with humans

Abstract

Social networks have been suggested as key media in the advertisement and recruitment of participants for human studies. They are appreciated due to their cost-effectiveness and apparent large-scale reach. Indeed, for a number of underfunded scientific studies, social networks effectively replace all other media in recruitment efforts.But, the organisation and operation of social networks not necessarily reflects the connections of a population in the real world. And, in contrast to other media, in social networks the rules that govern the spread of messages follow unstable ranking methods that sit entirely out of the control of investigators. This article reviews how social networks are managed environments that implement a variety of opportunistic regulations which control links between-users and the messages every user sees. Thus, their use as sole media in recruitment of participants for scientific trials would yield a non-representative biased sample of the population.