Judgment sample

A judgment sample, or expert sample, is a type of non-random sample that is selected based on the opinion of an expert.

Results obtained from a judgment sample are subject to some degree of bias, due to the sample's frame (i.e. the variables that define a population to be studied) and population not being identical.

A random sample would provide less bias, but potentially less raw information. 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.