Standardisation of initial performance requirements is an important first step towards like-for-like comparison of luminaire manufacturer claims.Performance over life is currently not in the scope of the IEC/PAS because of the still many uncertainties in this relatively new LED technology.For that purpose the suggested lifetime metric luminaire life will be further developed.For fair comparison of initial performance always ask for product specifications measured against an appropriate standard.When considering performance over time please forget about LM-80/TM-21 lumen maintenance data of LEDs used in a luminaire and look for luminaire life values expressed in lumen maintenance and abrupt failures of the complete system.It is important to remember not to mix up Apples & Pears since this will significantly improve the quality of your decision when evaluating claims from different LED luminaires.