efficiencysince
Efficiencysince is a conceptual metric that describes how the current efficiency of a system compares to its efficiency at a defined baseline event, as a function of the time elapsed since that event. The baseline is often the moment of commissioning, the most recent maintenance, calibration, or another reference point. The term is used in reliability engineering and performance monitoring to separate effects of aging, wear, or adjustment from other variables that influence output.
Mathematical framing commonly treats efficiencysince as the ratio η_since(t) = η(t) / η0, where η0 is the baseline
Measurement and use involve collecting performance data, normalizing by the baseline, and often applying smoothing or