You are using "Reliance on available subjects".
There are four types of sampling;
Reliance on Available Subjects
Purposive or Judgmental Sample
Snowball Sample
Quota Sample
Relying on available subjects, for example, ceasing individuals on a road corner as they pass by, is one strategy for inspecting, despite the fact that it is amazingly hazardous and accompanies numerous alerts. This strategy is sometimes alluded to as an accommodation test and does not enable the analyst to have any control over the representativeness of the example.