Snowball Sampling Recruitment Guidelines
Snowball sampling is a recruitment technique that involves asking current research participants to help identify other potential participants (i.e. referral). The potential participant must give their permission to the current participant to refer their name. The following considerations must be taken into account when using this type of recruitment strategy for research studies:
Snowball sampling may not be an acceptable recruitment strategy if you are conducting research on a sensitive/personal topic (e.g., HIV, abuse). There is the potential for privacy violations during the recruitment process if the research topic is sensitive or personal in nature. In such instances, the disclosing of personal information about a third party during the referral process could result in embarrassment or anger for potential research participants.
You must let current participants know that they will be asked to provide names for other potential participants; however, you must let them know that they are not required to provide this information for study purposes.
Current participants must be informed that their identity will be revealed to all potential participants whom they refer. You must include this information in the Letter of Information/Informed Consent Form (LOI/CF) [e.g., inclusion of a tick box to indicate “yes, you may reveal my identity to those participants I have referred.”]
Current participants cannot receive any compensation for providing referrals or be offered any incentives to provide referrals.
You must include the snowball recruitment script that will be read to both the current participants and the potential participants with your ethics application.
Example Script for Current Participants
Thank you for participating in my research study titled [study title]. Would you be willing to pass along the name and contact information of any friend/family/co-worker who may be interested in participating? There is no obligation for you to pass along this information, and there will be no penalty if you do not provide this information. We will be letting potential participants whom you refer know that you were the source of the referral. You also have the right to request that you are given time to notify the potential participants prior to us contacting them.
Example Script for Potential Participants
Hello. My name is [name] and I am conducting a research study titled [study title]. Your name was passed along to me by [participant name]. It was suggested that you may be interested in participating in my research study. Do you have time to hear about my study now, or to set up a time to discuss this further in the near future?
Snowball Sampling Recruitment Guidelines v.2018APR23