手法を比較

	適応型自然実験	差分の差 (Difference-in-Differences, DiD)
分野	実験計画法	計量経済学
系統	Process / pipeline	Regression model
提唱年	2000s–2010s (systematic application in policy and social science evaluation)	1994
提唱者	Synthesizes natural experiment tradition (Meyer 1995; Dunning 2012) with adaptive design principles (Wald 1947; Chow & Chang 2008)	Card & Krueger (canonical 1994 application); Angrist & Pischke (textbook treatment)
種類	Quasi-experimental adaptive research design	Causal inference / panel regression
原典	Dunning, T. (2012). Natural Experiments in the Social Sciences: A Design-Based Approach. Cambridge University Press. ISBN: 978-1107698000	Angrist, J. D., & Pischke, J.-S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton University Press. ISBN: 978-0691120355
別名	adaptive quasi-experiment, adaptive exogenous shock design, adaptive as-if randomization, sequential natural experiment	diff-in-diff, DiD, Farkların Farkı (Diff-in-Diff)
関連	4	5
概要	An adaptive natural experiment combines the causal logic of the natural experiment — exploiting real-world events that assign individuals to conditions in a plausibly exogenous way — with pre-specified adaptive monitoring rules that allow the analytic protocol to be modified based on accumulating data. This hybrid design is used in economics, epidemiology, and policy evaluation when the natural event unfolds over time and interim evidence can legitimately inform decisions about data collection scope, subgroup focus, or analytic strategy without compromising causal validity.	Difference-in-Differences is a causal-inference method that estimates the effect of an intervention by comparing how a treatment group and a control group change over time. Made famous by Card and Krueger's 1994 minimum-wage study and developed in Angrist and Pischke's Mostly Harmless Econometrics, it isolates the treatment effect as the difference between the two groups' before-after changes.