Snowball sampling is a sampling technique that can be used to obtain additional respondents from the respondents' circle of acquaintances.
Example: In step 1, we have one interviewee. This person names 4 people. These 4 people then also take part in the survey (step 2) and name a further 8 people in total. These 8 people are then also interviewed (step 3). With the help of these 8 people, a further 13 people are interviewed (step 4).
![Snowball sampling and number of actors for each step](/sites/default/files/inline-images/snowball_sampling_step-and-nr-actors.png)
How do I set up snowball sampling in MyNetworkmap?
We need an namegenerator element for the collection of the alteri and a nameinterpretator element for the e-mail addresses of the alteri.
For example:
![Survey configuration example for snowball sampling](/sites/default/files/inline-images/snowball_sampling_interview-element7.png)
You can find the snowball element in the element list:
The form for the snowball element could be filled out as follows, for example:
![Snowball element example](/sites/default/files/inline-images/snowball_sampling_interview-element2.png)
Alteri attribute containting the email: Please select the attribute whose attribute value contains the requested e-mail address.
Select the email address to which the snowball email should be sent: Specify the e-mail address to which the e-mails are to be sent here. The email addresses correspond to those of the users who are registered with MyNetworkmap for their organization (see top menue "Organization settings" > "Reserved team accounts and team members").
The text parts with "{....}" are placeholders. For example {ego_placeholder_1} will be replaced with the content of the attribute "name".
The {alteri_placeholder_2} will be replaced by the attribute value "questionnaireLink_examaple" (=personalized link).
Add the Snowball element to the end of the questionnaire. And test your survey:
![Example](/sites/default/files/inline-images/snowball_sampling_interview-element3.png)
After clicking on "next", you (or the person you have configured to receive the e-mails) should receive 3 emails with personalized survey links for each alteri.
Example email:
![Example email for snowball sampling](/sites/default/files/inline-images/snowball_sampling_interview-element5.png)
Here you can see the schematic process using a fictional example of a snowball sampling survey:
![Snowball sampling workflow and ego centric network analysis with MyNetworkmap](/sites/default/files/inline-images/snowball_flow.png)