Provide a short note highlighting major differences between nonprobability and probability sampling techniques?
Answer
Probability sampling is more robust in comparison as in this technique every sampling unit has a nonzero, known chance of getting selected in final sample. Nonprobability techniques conversely, don't use chance selection procedure. Instead, they depend on personal judgement of the researcher. Results obtained by using probability sampling can be generalized to target population within a specified margin of error through use of statistical methods. Put simply, probability sampling enables researchers to judge reliability and validity of findings in comparison to defined target population. Just in case of nonprobability sampling, selection of every sampling unit is unknown and hence, potential error between sample and target population can't be computed. Hence, generalizability of findings generated through nonprobability sampling is limited. When probability sampling techniques are robust in comparison one of the key disadvantages of such techniques is difficulty in attaining a current, complete and accurate listing of target population elements.