How accurate is our knowledge of galaxy bias?
  Observations of the clustering of galaxies can provide useful information
about the distribution of dark matter in the Universe. In order to extract
accurate cosmological parameters from galaxy surveys, it is important to
understand how the distribution of galaxies is biased with respect to the
matter distribution. The large-scale bias of galaxies can be quantified either
by directly measuring the large-scale ({\lambda} >~ 60 hinv Mpc) power spectrum
of galaxies or by modeling the halo occupation distribution of galaxies using
their clustering on small scales ({\lambda} <~ 30 hinv Mpc). We compare the
luminosity dependence of the galaxy bias (both the shape and the normalization)
obtained by these methods and check for consistency. Our comparison reveals
that the bias of galaxies obtained by the small scale clustering measurements
is systematically larger than that obtained from the large scale power spectrum
methods. We also find systematic discrepancies in the shape of the galaxy
bias-luminosity relation. We comment on the origin and possible consequences of
these discrepancies which had remained unnoticed thus far.
