方法对比

	事后研究设计	因果比较研究	描述性研究
领域	研究设计	研究设计	研究设计
方法族	Process / pipeline	Process / pipeline	Process / pipeline
起源年份	1960s (systematic codification); concept used in social science from early 20th century	1964	Late 19th century; formalized in social/behavioral sciences ~1960s–1980s
提出者	Formalized by Fred N. Kerlinger; foundational treatment by Donald T. Campbell and Julian C. Stanley	Fred N. Kerlinger	Francis Galton, Karl Pearson (early empirical tradition); formalized in social science by Fred Kerlinger
类型	Non-experimental quantitative research design	Non-experimental quantitative research design	Non-experimental quantitative research design
开创性文献	Kerlinger, F. N. (1964). Foundations of Behavioral Research. Holt, Rinehart and Winston.	Kerlinger, F. N. (1964). Foundations of Behavioral Research. Holt, Rinehart and Winston.	Creswell, J. W. (2014). Research Design: Qualitative, Quantitative, and Mixed Methods Approaches (4th ed.). Sage. ISBN: 978-1452226101
别名	after-the-fact research, retrospective non-experimental design, causal-comparative design, EPF design	ex post facto research, causal-comparative design, retrospective causal study, CCR	descriptive study, descriptive survey design, observational descriptive research, non-experimental descriptive research
相关	3	3	3
摘要	Ex post facto design is a non-experimental quantitative research approach in which the researcher investigates a phenomenon after it has already occurred, examining pre-existing differences between groups to explore potential causal or associative relationships. Because the independent variable cannot be manipulated — it happened in the past — the design relies on careful group selection, retrospective data collection, and statistical controls to approximate causal inference without experimental intervention.	Causal-comparative research is a non-experimental quantitative design in which the researcher compares two or more groups that already differ on an independent variable — one that was not manipulated — to investigate possible causes or consequences of that difference. Because group membership is pre-existing rather than randomly assigned, the design can suggest causal relationships but cannot establish them with the certainty of a true experiment. It is widely used in education, psychology, and social sciences when experimental manipulation is impractical or unethical.	Descriptive research is a non-experimental quantitative design that systematically documents the characteristics, frequencies, or distributions of variables in a defined population at a given point in time. It answers 'what is' questions — who, what, when, where, and how much — without manipulating variables or drawing causal conclusions. It is one of the most widely used research designs across the social, behavioral, health, and education sciences.