A method for compensating an OLED device having one or more light emitting elements having an output that changes with time or use, comprising: a) driving the OLED device at a known drive signal, and measuring a first current used by the light emitting elements and a first light output produced by the OLED device at the known drive signal; b) driving the OLED device for a time period after step (a); c) driving the OLED device at the known drive signal after step (b), and measuring a second current used by the light emitting elements and a second light output produced by the OLED device at the known drive signal; d) determining an aging function based on the measured first and second currents, known drive signal, and first and second light outputs; e) driving the OLED device for a period of time after step (d); f) measuring a third current used by the light emitting elements at the known drive signal after step (e); g) calculating a correction factor for the OLED device to correct for change in light output of the OLED device using the aging function determined in step (d) and the third current measured in step (f); and h) applying the correction factor to a drive signal for the OLED device.