A method for operating an LED light source, wherein the portion of the electrical power (Pout) fed to the LED light source during the operation that is converted into light (Plight) is determined on the basis of temperature measurements. On the basis thereof, a compensation factor (KAGE COMPENSATION) that compensates the aging of the LED light source can be determined, wherein a correlation factor that was determined at the start of the putting into service of the lamp is taken into account in order to determine the portion of the electrical power converted into light (Plight).