So sánh phương pháp

	Chọn mẫu có chủ đích theo tỷ lệ	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	1980s–2000s	1985 (Lincoln & Guba); elaborated 1990–2002 (Patton)
Người khởi xướng	Derived from purposive sampling tradition (Patton); formalized in mixed-methods literature	Lincoln & Guba; systematised by Michael Quinn Patton
Loại	Non-probability sampling with proportional allocation	Purposive qualitative sampling strategy
Công trình gốc	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage Publications. ISBN: 978-0761919711	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage. Chapter 5: Purposeful Sampling. ISBN: 978-0761919711
Tên gọi khác	proportional criterion sampling, quota-proportional purposive sampling, representational purposive sampling	maximum variation sampling, maximum diversity sampling, MVS, heterogeneous sampling
Liên quan	4	5
Tóm tắt	Proportional purposive sampling combines the intentional case selection of purposive sampling with proportional allocation across subgroups. Researchers first determine how each meaningful subgroup (e.g., gender, school type, professional role) is represented in the population, then deliberately select participants from each subgroup in those same proportions — using purposive judgment to ensure each selected case is information-rich and relevant to the research question.	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.