I act as an advisor for DronesBench http://www.dronesbench.com and we think there should also be some sort of drone efficiency certification for the consumer market (from 250g to about 4kg, under 250g they are toys according to EASA legislation draft), same as other electro-mechanical devices or machines, with a concise parameter to be sported on the drone's plate. Too much a difference from the value declared by the vendor may imply hidden defects of the drone and therefore the possibility of a crash. We are actively proposing our DronesBench Index to IEEE and EASA for the legislation to come, with encouraging response from IEEE at the preliminary level. It remains to be seen if and how things progress in a formal way.