手法を比較

	自然実験	ランダム化比較試験 (RCT)
分野	実験計画法	実験計画法
系統	Process / pipeline	Hypothesis test
提唱年	1990s (formal methodological articulation); earlier in epidemiology (John Snow, 1854)	1948
提唱者	Varied; systematized in econometrics and political science (e.g., Meyer 1995; Angrist & Krueger 1991)	James Lind (early precursor, 1747); modern formulation: Austin Bradford Hill & Medical Research Council (1948)
種類	Quasi-experimental research design	Interventional comparative study
原典	Meyer, B. D. (1995). Natural and quasi-experiments in economics. Journal of Business and Economic Statistics, 13(2), 151–161.	Schulz, K.F., Altman, D.G., Moher, D., for the CONSORT Group (2010). CONSORT 2010 Statement: Updated Guidelines for Reporting Parallel Group Randomised Trials. BMJ, 340, c332.
別名	natural quasi-experiment, naturally occurring experiment, exogenous shock design, as-if randomization	RCT, randomised controlled trial, clinical trial, Randomize Kontrollü Çalışma (RCT) Tasarımı
関連	3	7
概要	A natural experiment exploits a real-world event, policy, or circumstance that assigns individuals to treatment and control conditions in a way that is plausibly random — or at least exogenous to the outcome of interest. Because the researcher does not control assignment, it occupies a middle ground between a true randomized controlled trial and purely observational research, offering stronger causal leverage than conventional observational designs when the as-if randomization assumption holds.	A randomized controlled trial (RCT) is the gold standard experimental design in clinical and health research, in which participants are randomly allocated to a treatment group or a control group so that the effect of an intervention can be measured with the highest possible degree of internal validity. The modern parallel-group RCT was formalized by Austin Bradford Hill and the Medical Research Council in their landmark streptomycin trial of 1948, and its reporting is governed today by the CONSORT 2010 guidelines (Schulz et al., 2010).