  The Bardeen-Petterson general relativistic effect has been suggested as the
mechanism responsible for precession in some accretion disk systems. Here we
examine separately four mechanisms (tidally-induced, irradiation-induced,
magnetically-induced and Bardeen-Petterson-induced) that can lead to warping
and precession. We use a sample of eight X-ray binaries and four Active
Galactic Nuclei (AGNs) that present signatures of warping and/or precession in
their accretion disks to explore the viability of the different mechanisms. For
the X-ray binaries SMC X-1 and 4U 1907+09 all four mechanisms provide
precession periods compatible with those observed, while for Cyg X-1 and the
active galaxies Arp 102B and NGC 1068, only two mechanisms are in agreement
with the observations. The irradiation-driven instability seems incapable of
producing the inferred precession of the active galaxies in our sample, and the
tidally-induced precession can probably be ruled out in the case of Arp 102B.
Perhaps the best case for a Bardeen-Petterson precession can be achieved for
NGC 1068. Our results show that given the many observational uncertainties that
still exist, it is extremely difficult to confirm unambiguously that the
Bardeen-Petterson effect has been observed in any of the other sources of our
sample.
