First- and total-order sensitivity indices (equation 11) for the second series of runs, when varying seven GALFORM parameters (Table 2). Bottom panel: K-band luminosity function at z = 0 as in Fig. 4; grey lines show 10 randomly chosen galform models; the black line connects observational data from Driver et al. (2012); dashed vertical line corresponds to L*; the solid red line shows the best-fitting model. Top panels: first- and total-order (as labelled on the right) sensitivity indices of two variables (y-axis) for individual magnitude bins (x-axis), colour-coded by value between 0 (not sensitive) and 1 (most sensitive) as labelled by the colour bar at the top.