Risk Management is essential for development and production programs. Information about key project cost, (technical) performance, and schedule attributes is often uncertain or unknown until late in the program.
Risk issues that can be identified early in the program, which will potentially impact the program later, termed Known Unknowns and can be alleviated with good risk management.
Making these decisions in the presence of Uncertainty ‒ reducible and irreducible ‒ requires making estimates ‒ to assess the probability of occurance of reducible uncertainty and stochastic behaviour of irreducible uncertainty - and the impact of the risk created by these uncertanties on the probability of success of proejct.
‒Effective Risk Management 2nd Edition, Edmund Conrow, AIAA, 2003