手法を比較

	単一盲検自然実験	自然実験	単盲検ランダム化比較試験
分野	実験計画法	実験計画法	実験計画法
系統	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	Late 20th century (formalized practice)	1990s (formal methodological articulation); earlier in epidemiology (John Snow, 1854)	1948 (formalized); single-blind variant established in mid-20th century clinical trial methodology
提唱者	Conceptual synthesis of natural experiment tradition (Haavelmo, 1944; Campbell & Stanley, 1963) with single-blind methodology	Varied; systematized in econometrics and political science (e.g., Meyer 1995; Angrist & Krueger 1991)	Bradford Hill and colleagues (MRC streptomycin trial, 1948); blinding conventions codified in CONSORT guidelines
種類	Quasi-experimental design with partial blinding	Quasi-experimental research design	Experimental design — blinded randomized trial
原典	Dunning, T. (2012). Natural Experiments in the Social Sciences: A Design-Based Approach. Cambridge University Press. ISBN: 978-1107698000	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., & CONSORT Group. (2010). CONSORT 2010 statement: Updated guidelines for reporting parallel group randomised trials. BMJ, 340, c332.
別名	single-masked natural experiment, blinded quasi-experiment, single-blind exogenous assignment study	natural quasi-experiment, naturally occurring experiment, exogenous shock design, as-if randomization	single-masked RCT, single-blind RCT, single-blind trial, SB-RCT
関連	2	3	5
概要	A single-blind natural experiment leverages an exogenous, researcher-uncontrolled event — such as a policy change, lottery, or natural disaster — to create treatment and comparison groups, while applying single-blind procedures so that either the participants or the outcome assessors (but not both) are unaware of group assignment. This design combines the causal leverage of natural variation with reduced measurement bias from blinding.	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 single-blind randomized controlled trial (SB-RCT) is a rigorous experimental design in which participants are randomly assigned to treatment or control conditions while remaining unaware of which condition they have received. Investigators, outcome assessors, and data analysts are not blinded. By masking participants, the design eliminates placebo and nocebo response biases on the participant side, while preserving investigator flexibility to administer and monitor the intervention.