Non-probability sampling be used in certain circumstances.
There are some circumstances in which probability sampling may not be possible or preferred. The evaluation of smaller youth programs, when a small number of elements (under 20) to be elected, the key statistical properties of probability sampling are not applied. If you collect data from fewer than 20 people, a non-probability quota sampling to consider representative in terms of the important features is as effective as a probability sample.
Some programs work with sub-groups of youth such as street children and drug users. In these situations, it may be difficult or ...