Accuracy of fold change estimation. The fold change in expression levels between panels A and B was calculated based on six pair-wise comparisons across three experimental runs. (A) The distribution of fold change measurements are displayed for each ERCC standard based on 100 individual microarray features for each standard. Box-whisker plots reflect median, interquartile range, 10th and 90th percentile fold change values with dots indicating individual outliers. Expected values for fold changes are indicated by gridlines. (B) Microarray observed fold change values averaged across all 100 probe replicates are plotted against fold change measurements from RT-qPCR data as individual data points (n = 6 for each ERCC standard). Trendline indicates correlation analysis with calculated slope and Pearson's correlation coefficient (R).