Bias correction increases consistency of correlation with ER status within five clinical breast cancer studies. (a) CC coefficients are plotted for each possible pair of data sets, before and after bias correction. The largest improvement, indicated by a red circle, is between data sets from Sotiriou et al.  and Miller et al. . For these two data sets, two-dimensional histograms indicate the distribution of correlation coefficients between expression values and ER status for all probe sets (b) using uncorrected data and (c) after bias correction.
Eklund and Szallasi Genome Biology 2008 9:R26 doi:10.1186/gb-2008-9-2-r26