So sánh phương pháp

	Các Phương Pháp Lấy Mẫu Trong Nghiên Cứu	Phương pháp thu thập dữ liệu
Lĩnh vực	Phương pháp luận nghiên cứu	Phương pháp luận nghiên cứu
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1950	1980
Người khởi xướng	William G. Cochran and Leslie Kish (1950s–1970s)	Floyd Fowler (surveys); John Creswell, Robert DeVellis (qualitative and scale methodology)
Loại	Framework	Framework
Công trình gốc	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons.	Fowler, F. J. (2014). Survey Research Methods (5th ed.). SAGE Publications.
Tên gọi khác	sampling strategy, sampling design, probability and non-probability sampling	data gathering, measurement instruments
Liên quan	3	3
Tóm tắt	Sampling is the process of selecting a subset of individuals, observations, or units (the sample) from a larger population to study. Sampling methods are broadly classified into probability (random) and non-probability (non-random) approaches. Probability methods—random sampling, stratified sampling, cluster sampling, systematic sampling—enable statistical inference to the population and allow calculation of confidence intervals and margins of error. Non-probability methods—convenience, purposive, snowball, quota sampling—are practical for exploratory or qualitative research but do not support formal statistical generalization. Cochran's Sampling Techniques (1977) and Kish's Survey Sampling (1965) are foundational references; modern applications span surveys, experiments, qualitative studies, and clinical trials.	Data collection methods are the specific techniques and instruments used to gather information from research participants or sources. Common quantitative methods include surveys (questionnaires, interviews), physiological measurements (blood pressure, lab assays), behavioral observations, and administrative/secondary data (e.g., medical records, national registers). Qualitative methods include in-depth interviews, focus groups, observations, and document analysis. Selection and design of data collection instruments directly affect data quality, validity, and reliability. Floyd Fowler's work on survey methodology (1980s–2010s), Robert DeVellis's scale development approach, and John Creswell's frameworks for qualitative data collection provide systematic guidance.