Light & Engineering Vol. 23, No. 3, pp. 54-65, 2015 Svetotekhnika No. 5, 2015 INTERNATIONAL INTERLABORATORY COMPARISON IC 2013 EXPERIENCE AND PARTICIPATION RESULTS OF THE VNISI TESTING CENTRE Alexei A. Bartsev, Roman I. Belyaev, and Raisa I. Stolyarevskaya VNISI Open Company of S. I. Vavilov E-mail: bartsev@vnisi.ru ABSTRACT Between October 2012 to August 2013 an International Interlaboratory comparison IC 2013 light-emitting diode products measurements was undertaken by a group of international experts as part of a special programme of the International Energy Agency “IEA 4 E SSL Annex”. <...> During the following year, analysis and processing of the measurement results were carried out. <...> In September 2014, a fi nal report was published, which contained the data and measurement result analysis of all participants1. 54 laboratories from 18 countries took part in the measurements directly. <...> They performed measurements for similar lamps using similar methods shortly before the start of the IEA 4 E SSL Annex project. <...> Besides, data from 21 laboratories of the Asia Pacifi c Laboratory Accreditation Cooperation (APLAC) were included in the fi nal report. <...> Thus in total, measurement data from 110 laboratories worldwide were included in the IC 2013 fi nal report. <...> Every set contained four or fi ve types of lamps, including light-emitting diode lamps. <...> The parameters measured for each test sample included luminous fl ux, active power, luminous effi cacy, effective values of current and voltage, power factor, chromaticity coordinates, correlated 1 The laboratories specifi ed agreed to be entered into the published IEA 4 E Annex list. 55 chromatic temperature and colour rendition index. <...> This article considers the differences in measurements results obtained by participant laboratories, including the VNISI Testing Centre (VNISI TC), and between the measurement results obtained in the nucleus organising laboratories (NIST (USA), VSL (Europe), NLTC and AIST (Asia Pacifi c)). <...> The obtained results were processed according to ISO 13528 international standard requirements (z’-index indicator was determined). <...> In cases where a participant laboratory submitted evaluations of measurement uncertainties <...>