  Several recent studies have reported a mean size difference of about 20%
between the metal-rich and metal-poor subpopulations of globular clusters (GCs)
in a variety of galaxies. In this paper we investigate the possibility that the
size difference might be a projection effect, resulting from a correlation
between cluster size and galactocentric distance, combined with different
radial distributions of the GC subpopulations. We find that projection effects
may indeed account for a size difference similar to the observed one, provided
that there is a steep relation between GC size and galactocentric distance in
the central parts of the GC system and that the density of GCs flattens off
near the center in a manner similar to a King profile. For more centrally
peaked distributions, such as a de Vaucouleurs law, or for shallower
size-radius relations, projection effects are unable to produce the observed
differences in the size distributions.
