Final answer:
The technique where a survey is passed among qualifying subjects through their networks is called snowball sampling. It is useful for researching hard-to-reach populations and differs from quota, random, and stratified sampling methods.
Step-by-step explanation:
The sampling technique in which you send a research survey to a small group of subjects who meet your criteria and then ask them to share it with others who also meet those criteria is known as snowball sampling. This method leverages the networks of initial subjects to identify additional participants. It is particularly useful for reaching populations that are difficult to access using standard sampling methods. In contrast, quota sampling involves selecting a sample that reflects the characteristics of the whole population, random sampling gives each member of the population an equal chance of being selected, and stratified sampling involves dividing the population into strata and randomly sampling from each stratum.