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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Dear Testers<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Please see the paper “Key differences of performance test protocols for household biomass cookstoves” by Zhang, Y <i>et al</i> at<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><a href="http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6827753&queryText%3DKey+differences">http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6827753&queryText%3DKey+differences</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Abstract<o:p></o:p></p><p class=MsoNormal>“In this study, different ways of testing household biomass cooking stoves are compared and analyzed. The differences between test methods relate to the stove operation and data analysis methods, the fueling procedure, the end point selection, the choice of metrics and others factors. The influences of these differences were analyzed by using an induction heater. The results show the use of a pot lid or not, and the selection of the end point of the test have the greatest influence on the rated performance. Consequently test results provided by laboratories using different test methods will place the same stove-plus-fuel combination on significantly different performance ‘tiers’. Also the results show some metrics in popular tests should be reviewed. Some recommendations are provided for improving the accuracy and repeatability of test procedures and select metrics are defined for greater clarity.”<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The comment “some metrics in popular tests should be reviewed” is a polite way of saying they are not valid. This is a major issue when making performance comparisons. If the metric itself is not valid then the comparisons of it between products is not meaningful. One cannot trade money or products on the result.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>From the conclusions:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0mm;margin-right:0mm;margin-bottom:10.0pt;margin-left:36.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2;text-autospace:none'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>b)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>Some metrics still need to be revisited, even if they are generally agreed within the “stove enthusiast” community. National or international compulsory regulation of stove products as envisaged by ISO TC 285 must be based on credible science. The point of testing is to provide useful information. Selected indicators that meet specific needs must first be agreed and validated, and then a test method or methods developed to collect the information necessary to deliver product ratings that can be widely compared and accepted by the public.<o:p></o:p></span></p><p class=MsoNormal>The paper is accessible free through academic services. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards<o:p></o:p></p><p class=MsoNormal>Crispin<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>