So sánh phương pháp

	Lấy mẫu biến thiên tối đa dựa trên thực địa	Chọn mẫu trường hợp lệch chuẩn
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1990 (Patton); field application established through ecological and ethnographic practice in the 1990s–2000s	1990
Người khởi xướng	Michael Quinn Patton (maximum variation sampling); adapted for field research contexts	Michael Quinn Patton
Loại	Purposive qualitative/mixed-methods sampling strategy	Purposive qualitative sampling strategy
Công trình gốc	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage. [Maximum variation sampling discussed in Chapter 5] ISBN: 978-0761919711	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage Publications. ISBN: 978-0761919711
Tên gọi khác	field MVS, field-based purposeful maximum variation, maximum heterogeneity field sampling, diverse case field sampling	extreme case sampling, outlier sampling, negative case sampling, deviant-case selection
Liên quan	6	5
Tóm tắt	Field-based maximum variation sampling is a purposive strategy in which a researcher deliberately selects field sites, ecological plots, communities, or observational units that span the widest possible range of relevant characteristics. By maximising heterogeneity among selected units, the approach ensures that both common patterns shared across diverse conditions and unique features specific to particular contexts are documented, making findings robust across a broad spectrum of real-world variation.	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.