So sánh phương pháp

	Chọn mẫu có chủ đích	Lấy mẫu Biến thiên Tối đa
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát
Họ	Process / pipeline	Process / pipeline
Năm ra đời	Formalized ~1980–1990	1985 (Lincoln & Guba); elaborated 1990–2002 (Patton)
Người khởi xướng	Michael Quinn Patton (systematic articulation); roots in early qualitative inquiry	Lincoln & Guba; systematised by Michael Quinn Patton
Loại	Non-probability sampling strategy	Purposive qualitative sampling strategy
Công trình gốc	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. Chapter 5: Purposeful Sampling. ISBN: 978-0761919711
Tên gọi khác	judgmental sampling, selective sampling, criterion-based sampling, purposeful sampling	maximum variation sampling, maximum diversity sampling, MVS, heterogeneous sampling
Liên quan	4	5
Tóm tắt	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.	Maximum variation sampling is a purposive qualitative sampling strategy in which the researcher deliberately selects cases that span the widest possible range of variation on dimensions central to the study. The goal is not statistical representation but the identification of common patterns that cut across diverse cases as well as the documentation of the unique ways each context shapes the phenomenon under investigation.