  We investigate the accretion rate, bolometric luminosity, black hole (BH)
growth time and BH spin in a large AGN sample under the assumption that all
such objects are powered via thin or slim accretion discs (ADs). We use direct
estimates of the mass accretion rate, Mdot, to show that many currently used
values of Lbol and Ledd are either under estimated or over estimated because
they are based on bolometric correction factors that are adjusted to the
properties of moderately accreting active galactic nuclei (AGN) and do not take
into account the correct combination of BH mass, spin and accretion rate. The
consistent application of AD physics to our sample of Sloan Digital Sky Survey
(SDSS) AGN leads to the following findings: 1. Even the most conservative
assumption about the radiative efficiency of fast accreting BHs shows that many
of these sources must contain slim ADs. We illustrate this by estimating the
fraction of such objects at various redshifts. 2. Many previously estimated BH
growth times are inconsistent with the AD theory. In particular, the growth
times of the fastest accreting BHs were over estimated in the past by large
factors with important consequences to AGN evolution. 3. Currently used
bolometric correction factors for low accretion rate very massive SDSS BHs, are
inconsistent with the AD theory. Applying the AD set of assumptions to such
objects, combined with standard photoionization calculations of broad emission
lines, leads to the conclusion that many such objects must contain fast
spinning BHs.
