How should research involving “snowball samples” be handled from a human subjects perspective?
In a “snowball sample” each respondent is asked to suggest other persons for inclusion in the research. These persons are then contacted to see if they wish to serve as research participants. This is a valid procedure often used by investigators who seek to recruit from populations for which adequate sample frames are not available. For example, a researcher seeking to study patterns of informal leadership in a community may ask individuals to name others who are influential in a community. Similarly, studies of the diffusion of ideas and acceptance of new technologies can be traced through scientific and medical communities. Snowball samples in and of themselves do not necessarily pose a risk for human subjects. IRBs should follow the normal procedure of examining the project for risks of harm commensurate with normal life. Each respondent is given the opportunity to participate or to decline participation. For studies studying sensitive topics, study protocols should adhere to the re
