Abstract: The present invention discloses a system and method for estimating a change point time in a manufacturing process. The change point estimate is estimated by a change point estimator after receiving an alarm from a statistical process control chart. The change point estimate is estimated by estimating the point of a process before and after a particular point in time and declaring the point with the maximum absolute difference to be the change point time. In the present invention there are three versions for estimating the change point estimate. After estimating the change point time any other likely change point times are then determined and used to match the dates of those changes to any possible changes in the product variables that occurred during the manufacturing process. A source causing the change in the process is then identified, allowing an engineer to provide the necessary corrective action to remedy the change.