Preparing for project’s Schedule Quantitative Risk Analysis is like painting a wall. The wall preparation takes the longest before the final paint coat is applied. The last layer becomes as essential as sanding debris and covering all holes with joint compounds. Up to 80 percent of the Schedule Quantitative Risk Analysis (SQRA) effort is preparing the risk model. The remaining twenty percent (20%) is on the proper use of the tool, e.g., OPRA, previously called PertMaster, Deltek Acumen Risk, and others.
If the schedule is not of good quality and not modeled correctly, then the 80% effort amounted to nothing. The resulting assessment can become unreliable if not all wrong that it can derail the project!
A schedule accepted for risk analysis that dramatically deviates from the project execution plan creates troubling scenarios that keep project managers reasonably on edge.
One must not forget the cardinal rule that the schedule is a reflection of the plan.
If the construction execution plan violates the overall execution strategy, the project is a good candidate for failure. Everyone should be on deck and looking at the same goal if it is to succeed.