手法を比較

	リスクベースのシックスシグマDMAIC	フォールトツリー解析 (FTA)
分野	実験計画法	信頼性
系統	Process / pipeline	Process / pipeline
提唱年	1990s–2000s	1981
提唱者	Motorola (Six Sigma, 1986); risk integration formalized in quality engineering literature from the 1990s onward	Vesely et al. (US NRC Fault Tree Handbook)
種類	Process improvement methodology with embedded risk assessment	Deductive top-down failure analysis
原典	De Mast, J., & Lokkerbol, J. (2012). An analysis of the Six Sigma DMAIC method from the perspective of problem solving. International Journal of Production Economics, 139(2), 604–614.	Vesely, W. E., Goldberg, F. F., Roberts, N. H., & Haasl, D. F. (1981). Fault Tree Handbook (NUREG-0492). U.S. Nuclear Regulatory Commission.
別名	Risk-integrated DMAIC, DMAIC with risk analysis, Risk-aware Six Sigma, RB-DMAIC	FTA, Fault Tree Method, Top-Down Reliability Analysis, Hata Ağacı Analizi
関連	6	3
概要	Risk-based Six Sigma DMAIC embeds structured risk assessment — typically failure mode and effects analysis (FMEA), risk priority numbers (RPN), or probabilistic risk tools — at each stage of the standard DMAIC cycle. The goal is not only to reduce defects and variation but to prioritize improvement actions by their risk consequence, ensuring that critical failure modes are addressed before less impactful ones. It is widely applied in manufacturing, healthcare, aerospace, and process industries where both quality and safety are at stake.	Fault Tree Analysis (FTA) is a top-down, deductive reliability method that begins with an undesired top-level failure event and systematically traces backward through chains of contributing causes using Boolean logic gates (AND, OR). First formalized by Watson at Bell Telephone Laboratories in 1961 and later standardized by Vesely, Goldberg, Roberts, and Haasl in the landmark 1981 NRC Fault Tree Handbook, FTA has become a cornerstone of quantitative risk assessment in nuclear, aerospace, and industrial safety engineering.