So sánh phương pháp

	Chọn mẫu có chủ đích theo tỷ lệ	Chọn mẫu hạn ngạch
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1980s–2000s	1930s
Người khởi xướng	Derived from purposive sampling tradition (Patton); formalized in mixed-methods literature	Developed in market research and opinion polling, notably applied by George Gallup in the 1930s
Loại	Non-probability sampling with proportional allocation	Non-probability sampling design
Công trình gốc	Patton, M. Q. (2002). Qualitative Research and Evaluation Methods (3rd ed.). Sage Publications. ISBN: 978-0761919711	Moser, C. A., & Kalton, G. (1972). Survey Methods in Social Investigation (2nd ed.). Heinemann. ISBN: 978-0435827496
Tên gọi khác	proportional criterion sampling, quota-proportional purposive sampling, representational purposive sampling	quota-controlled sampling, quota selection, non-probability quota 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.	Quota sampling is a non-probability technique in which the researcher pre-specifies how many units to recruit from each subgroup (quota cell) defined by one or more control variables such as age, gender, or occupation. Interviewers or data collectors then use their own judgment to find and enroll participants until each cell is filled. The method guarantees the sample mirrors the population on the control variables but does not provide the randomness needed for classical statistical inference.