Abstract: The method and system for managing a project with multiple tasks and milestones by defining probabilities of key project events and assessing their performance risk. Each task of the project is described as a waveform propagating from this task to an assigned milestone, and each milestone is described as a coherent superposition of task waveforms. The probability of any milestone is obtained by comparison of probabilities of non-perturbed and perturbed milestone, which caused by delay of a task or combination of tasks.