原文地址：http://blog.csdn.net/jameszhou/archive/2007/06/24/1664424.aspx

PMBOK(2004 3rd 英) P257（中文版P257）关于风险定量分析模型技术中有一种技术叫敏感性分析(SensitivityAnalysis),用于比较各种风险在其他风险处于基准水平的情况下对项目整体产生的影响大小，从而来找出影响最大的风险。龙卷风图(tornadodiagram)是一种常用的技术，书中没有详细说明龙卷风图,也没有图例。

http://international.fhwa.dot.gov/riskassess/risk_hcm06_04.htm 给出了龙卷风的解释，并且给出了图例：

Sensitivityanalysis is a primary modeling tool that can be used to assist invaluing individual risks, which is extremely valuable in riskmanagement and risk allocation support. A "tornado diagram" is a usefulgraphical tool for depicting risk sensitivity or influence on theoverall variability of the risk model. Tornado diagrams graphicallyshow the correlation between variations in model inputs and thedistribution of the outcomes; in other words, they highlight thegreatest contributors to the overall risk.

The tornado diagramhas a central vertical axis from which bars extend left and right,their length corresponding to the influence of the factors theyrepresent on risk. The bars are ordered so that they decrease ininfluence as they go down.





上面的图形是不是很像龙卷风。