Tornado View Overview
The Tornado View is a specific view that shows the relative importance of random variability in the duration of individual activities in determining the variability in the overall project duration.
This view takes the form of a set of bars representing the sensitivity of the project to each activity and is normally sorted in descending order. The bars decrease in length from the top to the bottom of the chart, making it resemble a tornado pattern.
The Tornado View is based upon the Sensitivity Index, which is calculated as:
(Standard Deviation of Activity Duration * Probability that activity is critical)/ Standard deviation of project duration
Although the sensitivity is expressed as a percentage, the percentages can occasionally exceed 100 due to mixed calendars.