According to the US Government Accountability Office, in 2008 nearly 70% of the US Defense 96 biggest weapons programs were over budget. Congress instituted the Weapon Systems Acquisition Reform Act (WSARA) of 2009 to improve the organization and procedures of the DoD acquisition process. During this period, the cost community was primarily producing estimates based on most likely inputs, lacking incorporation of the full range of possible outcomes for the inputs. Studies were underway experimenting with incorporating monte carl simulation techniques into our cost estimating processes and WSARA provided the push that made it a requirement. The Joint Agency Cost Schedule Risk Uncertainty Handbook (JA CSRUH) describes the best practice techniques to model cost estimating uncertainty in order to calculate and report cost risk. This session shares thoughts and insights on the JA CSRUH and how it spurred major improvements in DoD’s acquisitions.