So sánh phương pháp

	Lấy mẫu Biến thiên Tối đa Đa cấp	Chọn Mẫu Có Chủ Đích Đa Cấp
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1990s–2000s	1980s–1990s
Người khởi xướng	Synthesized from Patton's maximum variation sampling (1990) and multi-level survey design traditions	Derived from Patton's purposive sampling framework; formalized in multi-site qualitative and mixed-methods research
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. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage. ISBN: 978-0761919711
Tên gọi khác	hierarchical maximum variation sampling, nested maximum diversity sampling, multi-tier purposive variation sampling, MLMVS	hierarchical purposive sampling, nested purposive sampling, multi-tier purposive sampling, multi-site purposive sampling
Liên quan	5	5
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.	Multi-level purposive sampling applies purposive selection criteria at two or more nested levels of a research hierarchy — for instance, first selecting sites or organizations, then selecting participants within each site. This layered approach allows researchers to align the theoretical logic of purposive sampling with the real-world structure of complex, hierarchical populations, making it especially valuable in multi-site qualitative studies and mixed-methods research.