  Using a large sample of quasar spectra from the SDSS, we examine the
composite spectral trends of quasars as functions of both redshift and
luminosity, independently of one another. Aside from the well known Baldwin
effect (BE) -- the decrease of line equivalent width with luminosity -- the
average spectral properties are remarkably similar. Host galaxy contamination
and the BE are the primary causes for apparent changes in the average spectral
slope of the quasars. The BE is detected for most emission lines, including the
Balmer lines, but with several exceptions including NV1240A. Emission line
shifts of several lines are associated with the BE. The BE is mainly a function
of luminosity, but also partly a function of redshift in that line equivalent
widths become stronger with redshift. Some of the complex iron features change
with redshift, particularly near the small blue bump region.
