So sánh phương pháp

	Lấy mẫu trường hợp lệch dựa trên thực địa	Lấy mẫu trường hợp điển hình
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1980s–1990s (purposive/deviant case sampling literature)	1980s (systematized in Patton 1990/2002)
Người khởi xướng	Michael Quinn Patton; Yvonna Lincoln & Egon Guba	Michael Quinn Patton
Loại	Purposive qualitative sampling strategy	Purposive qualitative sampling strategy
Công trình gốc	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
Tên gọi khác	field deviant case sampling, outlier case sampling in field research, extreme case sampling in fieldwork, in-situ deviant case sampling	typical case selection, modal case sampling, representative case sampling, average case sampling
Liên quan	5	5
Tóm tắt	Field-based deviant case sampling is a purposive strategy that deliberately selects cases deviating markedly from an established pattern or norm, with data collected through direct fieldwork — observation, in-situ interviews, and ethnographic engagement — in the participants' natural settings. By studying outliers on-site, researchers gain contextually grounded insight into why and how certain cases diverge from the typical pattern.	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.