So sánh phương pháp

	Lấy mẫu Biến thiên Tối đa Đa cấp	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	1990s–2000s	Formalized ~1980–1990
Người khởi xướng	Synthesized from Patton's maximum variation sampling (1990) and multi-level survey design traditions	Michael Quinn Patton (systematic articulation); roots in early qualitative inquiry
Loại	Purposive qualitative/mixed-methods sampling design	Non-probability sampling strategy
Công trình gốc	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage. [Chapter 5: Maximum variation sampling and purposeful sampling strategies] ISBN: 978-0761919711	Patton, M. Q. (1990). Qualitative Evaluation and Research Methods (2nd ed.). Sage. ISBN: 978-0803937796
Tên gọi khác	hierarchical maximum variation sampling, nested maximum diversity sampling, multi-tier purposive variation sampling, MLMVS	judgmental sampling, selective sampling, criterion-based sampling, purposeful sampling
Liên quan	5	4
Tóm tắt	Multi-level maximum variation sampling is a purposive strategy that deliberately selects cases at two or more nested organizational levels — such as schools within districts, or patients within clinics — while maximizing heterogeneity on key dimensions at each level. The aim is to capture the full range of variation within a hierarchically structured population so that patterns common across diverse contexts can be identified and context-specific differences can be documented with credibility.	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.