مقایسهٔ روش‌ها

	نمونه‌گیری هدفمند	نمونه‌گیری موردی معمول
حوزه	روش‌شناسی پیمایش	روش‌شناسی پیمایش
خانواده	Process / pipeline	Process / pipeline
سال پیدایش	Formalized ~1980–1990	1980s (systematized in Patton 1990/2002)
پدیدآور	Michael Quinn Patton (systematic articulation); roots in early qualitative inquiry	Michael Quinn Patton
نوع	Non-probability sampling strategy	Purposive qualitative sampling strategy
منبع بنیادین	Patton, M. Q. (1990). Qualitative Evaluation and Research Methods (2nd ed.). Sage. ISBN: 978-0803937796	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage Publications. ISBN: 978-0761919711
نام‌های دیگر	judgmental sampling, selective sampling, criterion-based sampling, purposeful sampling	typical case selection, modal case sampling, representative case sampling, average case sampling
مرتبط	4	5
خلاصه	Purposive sampling is a non-probability strategy in which the researcher deliberately selects participants, documents, or cases that are information-rich with respect to the research question. Rather than drawing units at random, the researcher applies explicit criteria aligned with the study's purpose, maximising the depth and relevance of the data collected. It is the default sampling logic in most qualitative research designs and is also used in mixed-methods and applied evaluative work.	Typical case sampling is a purposive strategy in which the researcher deliberately selects cases that represent what is ordinary, normal, or most common within a target group. Rather than seeking outliers or the widest possible variation, the goal is to illustrate and communicate what a typical experience, program, or phenomenon looks like to stakeholders or audiences unfamiliar with it. The strategy is widely used in qualitative evaluation research and program reporting.