To select a sensitivity chart view, in the sensitivity chart menu bar, select View, and then one of the following:
Contribution to Variance, the default—This view helps answer questions such as “What percentage of the variance or uncertainty in the target forecast is caused by assumption X?” The variance contribution percentages are displayed after the respective assumptions. Contribution to variance is calculated by squaring the rank correlation coefficients and normalizing them to 100%. The result is only an approximation and is not precisely a variance decomposition.
Rank Correlation—Crystal Ball calculates sensitivity by computing rank correlation coefficients between every assumption and every forecast while the simulation is running. Positive coefficients indicate that an increase in the assumption is associated with an increase in the forecast. Negative coefficients imply the opposite situation. The larger the absolute value of the correlation coefficient, the stronger the relationship.
Sensitivity Data—This view shows contribution to variance and rank correlation for each assumption in numeric form.
Both Rank Correlation view and Contribution to Variance view display the direction of each assumption’s relationship to the target forecast. Assumptions with a positive relationship have bars on the right side of the zero line. Assumptions with a negative relationship have bars on the left side of the zero line. To show just the absolute magnitude of the relationship, you can change the Chart Type preference setting described in Table 9 to Bar (Magnitude).