手法を比較

	クラスターランダム化フラクショナル要因実験	適応実験
分野	実験計画法	実験計画法
系統	Process / pipeline	Process / pipeline
提唱年	1950s (fractional factorial); 1980s-1990s (cluster-randomized extensions)	1940s–1970s (sequential foundations); formalised in clinical and behavioural research by 1980s–2000s
提唱者	Box, Hunter & Hunter (fractional factorial foundations); Murray & colleagues (group-randomized trial methodology)	Abraham Wald (sequential analysis foundation); expanded by Robbins, Armitage, and others
種類	Experimental design (compound)	Experimental research design
原典	Box, G. E. P., Hunter, J. S., & Hunter, W. G. (2005). Statistics for Experimenters: Design, Innovation, and Discovery (2nd ed.). Wiley. ISBN: 978-0471718130	Chow, S. C., & Chang, M. (2008). Adaptive Design Methods in Clinical Trials. Chapman and Hall/CRC. ISBN: 978-1584886761
別名	CR-FFE, cluster-randomized fractional factorial design, group-randomized fractional factorial trial, CRFFD	adaptive design, response-adaptive randomization, adaptive trial, adaptive randomization
関連	5	5
概要	A cluster-randomized fractional factorial experiment combines two design principles: randomization is applied to intact groups (clusters such as schools, clinics, or communities) rather than individuals, and only a carefully chosen fraction of all possible factor-level combinations is tested. This pairing makes it practical to screen or evaluate multiple intervention components simultaneously in settings where individual randomization is infeasible, while keeping the number of required clusters manageable.	An adaptive experiment is an experimental design in which pre-specified rules allow the protocol to be modified — such as reallocating participants to better-performing arms, stopping early for efficacy or futility, or changing sample size — based on accumulating interim data, while maintaining statistical validity. Adaptive designs are widely used in clinical trials, behavioural economics, and online platform testing to improve efficiency and ethics without sacrificing inferential rigour.