Bias parameter b as a function of bolometric luminosity for our RLQs and RQQs in the ranges 0.3 ≤ z ≤ 1.0 (left) and 1.0 ≤ z ≤ 2.0 (right). Errors in the L_bol axis are the dispersion values for each different quasar sample. The solid lines in both panels denote the predicted bias luminosity evolution according to the Shen (2009) model, which predicts that quasar activity is triggered by galaxy mergers.