Quasar variability: correlations with amplitude
  The relation between quasar variability and parameters such as luminosity and redshift has been a matter of hot debate over the last few years with many papers on the subject. Any correlations which can be established will have a profound effect on models of quasar structure and evolution. The sample of quasars in ESO/SERC field 287 contains over 600 quasars in the range 0 < z < 3.5 and is now large enough to bin in luminosity and redshift, and give definitive measures of the correlations. We find no significant correlation between amplitude and redshift, except perhaps at very low redshift, but an inverse correlation between amplitude and luminosity. This is examined in the context of various models for quasar variability. 
M.R.S. Hawkins