In clinically comparing a new measurement technique with an established technique, it is often necessary to see if they agree enough for the new one to replace the old one. Such studies are often subject to inappropriate analysis, including using correlation coefficients. The use of correlation is misleading. An alternative approach, based on graphic techniques and simple calculations, is described with the link between this analysis and the evaluation of repeatability. (Lancet, 1986; i: 307-310) @MISC Bl_statisticalmethods Bl_statisticalmethods, author – « J. Martin Bl and Douglas G. Altman, » title – « METHODES STATISTICS FOR THE ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENT, » year – correlation coefficient new alternative method of measuring the clinical measurement technique.