GeezerVison

A judgment sample, also known as an expert or purposive sample, is a type of non-random sample, where a researcher or expert selects the sample based on who they believe would be most useful or appropriate for the study.^[1][2]

Results obtained from a judgment sample are subject to some degree of bias and may be hard to generalize, due to the chosen sample not representing the larger population.^[1]

A random sample would provide less bias, but potentially less raw information.^[3] The pitfalls of this system are significant because of bias, limited statistical methods, and limits to an expert's ability to choose a good sample.