  BL Lacertae objects are an extreme subclass of AGNs showing rapid and
large-amplitude variability, high and variable polarization, and core-dominated
radio emissions. If a strong beaming effect is the cause of the extreme
observation properties, one would expect that these properties would be
correlated with each other. Based on the relativistic beaming model,
relationships between the polarization and the magnitude variation in
brightness, as well as the core- dominance parameter are derived and used
statistically to compare with the observational data of a BL Lacertae object
sample. The statistical results are consistent with these correlations, which
suggests that the polarization, the variation, and the core-dominance parameter
are possible indications of the beaming effect.
