Final answer:
Snowball sampling is a criterion sampling strategy commonly used with purposive sampling. It involves using a participant's network to recruit additional participants for qualitative research.
Step-by-step explanation:
A criterion sampling strategy commonly used with purposive sampling is the snowball sampling strategy. This strategy involves one participant using their network to recruit additional participants. It is commonly used in qualitative research, especially in populations that may be difficult to reach or recruit. The initial participant(s) recruit potential participants, either by providing their contact information or through an established relationship.