• Deciding the proper level of detail for the risk analysis (the level of aggregation of tasks or costs);
• Assuring relevant data in order to determine the probability distributions for task durations and the component
costs. Particular distributions, such as the triangle one are usually used based on mean and variance estimation
of the experts.
• Dealing with the correlations between task durations and costs. These correlations should be taken into
account when specifying probability distributions. To elicit multivariate distributions is far a more difficult
task than in the case of univariate one. In addition, the duration and cost random variables can only take
positive values. The constraints on correlated positive random variables are more difficult and far less
intuitive than in the case of normal distributions, where the correlations between an unlimited set of normal
random variables can be specified arbitrarily.