A system calculates a first ratio of a prediction error variance of a model of a controller error, and the lesser of a variance of a prediction error of a naïve predictor model and a variance of a controller error. The system rates a process controller as a function of the first ratio. The system also calculates a second ratio of a variance of the controller error and a variance of the prediction error of the naïve predictor model. The system rates the process controller a function of the second ratio. The system uses the first ratio, second ratio, other ratios, and discrete indicators in determining an embedded fusion for loop performance monitoring in the process controller and for displaying a value as a measure of the loop performance.