What is the nonprobability sampling method that identifies initial respondents to locate additional participants?

The nonprobability sampling method that identifies initial respondents to locate additional participants is snowball sampling. This approach is particularly useful in research where participants may be hard to access or where the target population is relatively small and interconnected.

In snowball sampling, researchers start with a small group of initial participants who meet the criteria for the study. These respondents are then asked to refer other participants, hence the term "snowball," as the sample size can grow with each referred participant. This method is valuable for qualitative research and situations where traditional sampling methods might not be feasible due to the nature of the population being studied, such as subcultures or specific demographic groups.

Stratified random sampling involves dividing the population into subgroups and randomly selecting samples from each subgroup, which doesn’t focus on locating further participants based on initial respondents. Systematic random sampling relies on a fixed interval to select participants from a list, and it does not utilize referrals. Convenience sampling entails choosing participants who are easiest to reach, rather than using referrals from current participants to build the sample size.