Effect of polarization errors on B estimates and accuracy of the correction method. Estimation of B as a function of GC content in simulated data sets: B = 0 for any GC content (A,C), and B linearly increases with GC content (B,D) (red lines in A,B). For a given simulated data set (= correctly orientated data, red lines), polarization errors (eneutral = eWS = eSW = 0.03) were secondarily added (= observed data). B values were estimated using the model without error correction (M1) (see main text and Supplemental Table S1) and with error correction (M1*). Box plots correspond to the B estimates of 100 correctly orientated data sets using the M1 model (red), 100 observed data sets using the M1 model (dark blue), 100 observed data sets using the M1* model (light blue). Figure parts C and D show the correlation between B values estimated from correctly orientated data with the M1 model and B values estimated from observed data with the M1* model. The regression line is indistinguishable from the diagonal y = x.
