Performance and robustness of RNAi screens. (A) Reproducibility with Pearson correlation coefficient of R = 0.65 for duplicate RNAi screens conducted in THP-1 at target EC₃₀. (B) Transfection efficiency for TF-1 and THP-1. Reduction in relative cell number was calculated as a percentage of the universal lethal control (n = 16) versus the median value for all 572 siRNA as a readout for transfection efficiency. (C) Ara-C growth-inhibitory effects. Viability calculated as the percentage inhibition of the median of NS-siRNA (n = 16) over NS-siRNA + Ara-C (n = 16). (D) Nonspecific effects on relative cell number calculated as the fraction of NS-siRNA (median, n = 16) versus buffer/control medium for both NS-siRNA–only and NS-siRNA + Ara-C. TF-1 screens were performed at higher (EC₇₀) and lower (EC₃₀) Ara-C concentrations. RLUs indicates relative luminescene units.