مقایسهٔ روش‌ها

	نمونه‌گیری هدفمند تطبیقی	نمونه‌گیری موارد انحرافی
حوزه	روش‌شناسی پیمایش	روش‌شناسی پیمایش
خانواده	Process / pipeline	Process / pipeline
سال پیدایش	1980s–1990s	1990
پدیدآور	Rooted in Patton's purposive sampling typology; adaptive dimension from iterative qualitative inquiry traditions	Michael Quinn Patton
نوع	Qualitative sampling strategy	Purposive qualitative sampling strategy
منبع بنیادین	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage Publications. ISBN: 978-0761919711	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage Publications. ISBN: 978-0761919711
نام‌های دیگر	iterative purposive sampling, emergent purposive sampling, adaptive qualitative sampling, dynamic purposive sampling	extreme case sampling, outlier sampling, negative case sampling, deviant-case selection
مرتبط	5	5
خلاصه	Adaptive purposive sampling is a qualitative strategy in which the researcher begins with explicitly stated, theory-driven selection criteria and then deliberately revises those criteria as data collection proceeds and new understanding emerges. Unlike fixed purposive sampling — where criteria are locked in before fieldwork — the adaptive variant treats the sampling frame as a working hypothesis that is refined in response to early findings, enabling the study to follow the evidence into unexpected but analytically important directions.	Deviant case sampling is a purposive qualitative sampling strategy in which the researcher intentionally selects cases that are unusual, exceptional, or markedly different from the norm — outliers, extreme successes, or conspicuous failures. The goal is not statistical representation but deep learning from cases that illuminate the boundaries of a phenomenon, challenge prevailing assumptions, or reveal processes that typical cases obscure.