n.choosing, as part of appraisal, a portion of a body of records for permanent retention through subjective criteriaHull 1981, 11Only one remove from the taking of examples is the more systematized method of qualitative or purposive sampling and nothing gives rise to more uncertainty than this technique, for this process is, and must be, essentially subjective. It takes place when a selection is made on a preconceived set of criteria, the intention being to retain the most significant or important records of a class or series. The similarity to the example is clearly apparent, but the process is carried out, not because it seems desirable to retain a specimen, but because certain material, in an otherwise destructible class, is considered to be of special value for research.Cook 1991b, 34Purposive sampling appears to be more scientific, for by this method experts try through research to isolate a characteristic or feature of the population that they judge to be representative of the whole, and then choose a sample based on that characteristic with the intention of reflecting whole.Zach and Peri 2010, 111Selection criteria for the interviews also included size/type of institution, type of program implemented or planned, geographic location, and scheduling constraints. Use of such selection criteria is consistent with theoretical and/or purposive sampling techniques.Zhang and Mauney 2013, 179We used a mixed-methods research design for this study. In May of 2011, we began to collect data using a combination of systematic random sampling and purposive sampling to identify examples of digital archives and special collections located in North America. Efforts were made to include sources with a broad coverage of digital collections containing archival and special collection materials.Benoit 2017, 413The data were generated by 60 participants divided equally through purposive sampling based on domain knowledge of the civil rights movement in Milwaukee.Hunter 2020, 63–64Archivists use purposive sampling when they are not concerned about obtaining a representative sample. Instead, the archivist makes a judgment about which individual items or cases merit retention. Such subjective sampling is very familiar to archivists; in fact, it is very similar to a standard archival appraisal decision. ¶ The danger with any type of purposive sampling is that it is susceptible to bias. The judgment of a fallible human being is at the heart of the decision to retain or destroy an item. In order to make an informed decision, the archivist must have some expertise in the subject area and a familiarity with research trends in the discipline.
Purposive sampling, synonymous with subjective sampling, is also less commonly called purposeful sampling, qualitative sampling, or selective sampling.