UV luminosity functions at z = 8 by setting the scatter in the galaxy properties to either zero (blue line), equal to the fiducial values from Table 1 (orange line), and increased by factors of 2 (green line) or 3 (red line). Top: runs where the scaling relations are normalised to have the same linear mean. Bottom: runs where log-normal scatter is simply added to a fixed log-log mean relation. In both cases increasing scatter results in a flattening of the relation; however, in the later case it also results in significantly brighter galaxies overall.