So sánh phương pháp

	Lấy mẫu biến thiên tối đa dựa trên thực địa	Chọn mẫu có chủ đích
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	Formalized ~1980–1990
Người khởi xướng	Michael Quinn Patton (maximum variation sampling); adapted for field research contexts	Michael Quinn Patton (systematic articulation); roots in early qualitative inquiry
Loại	Purposive qualitative/mixed-methods sampling strategy	Non-probability 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. (1990). Qualitative Evaluation and Research Methods (2nd ed.). Sage. ISBN: 978-0803937796
Tên gọi khác	field MVS, field-based purposeful maximum variation, maximum heterogeneity field sampling, diverse case field sampling	judgmental sampling, selective sampling, criterion-based sampling, purposeful sampling
Liên quan	6	4
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.	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.