  There are many priority deriving methods for pairwise comparison matrices. It
is known that when these matrices are consistent all these methods result in
the same priority vector. However, when they are inconsistent, the results may
vary. The presented work formulates an estimation of the difference between
priority vectors in the two most popular ranking methods: the eigenvalue method
and the geometric mean method. The estimation provided refers to the
inconsistency of the pairwise comparison matrix. Theoretical considerations are
accompanied by Montecarlo experiments showing the discrepancy between the
values of both methods.
