Earned Value curve (Planned Value, Costs and Earned Value) helps you see at any time if a delay will cost more than what we have in the budget. This delay may be in non-critical tasks in the best or worst, be in the critical path (GANTT). These situations can be avoided by good management which includes risk assessment. Place the activities that have to be done if an unforeseen event happens. With this definition, one can use Monte Carlo methods to tell the probability of success and how much time and money it will finally cost. In addition one may add the estimation uncertainty for critical activities. What will be the impact on the estimate to complete the project? All this, should be done before starting the project. During the execution of the project simulations can be used constantly. Define an early warning system which indicates critical situations early enough to take actions.