  Here we discuss the jet production efficiency in a sample of 17 young radio
galaxies with measured redshifts, kinematic ages, and nuclear X-ray fluxes, for
which the observed luminosities of compact jets/lobes and accretion disks
correspond to the same episode of the AGN activity. For the targets, we analyze
the available optical data, estimating the bolometric luminosities of the
accretion disks $L_{\rm bol}$, and the black hole masses; we also derive the
minimum jet kinetic luminosities, $P_{\rm j}$. With such, we investigate the
distribution of our sample in the three-dimensional space of the accretion rate
$\lambda_{\rm Edd} \equiv L_{\rm bol}/L_{\rm Edd}$, the nuclear X-ray
luminosity $L_{\rm X}$ considered here as a limit for the emission of the disk
coronae, and $P_{\rm j}$, expressing the latter two parameters either in the
Eddington units, or in the units of the disk luminosity. We find that (i) the
accretion rate $\lambda_{\rm Edd}$ in our sample is distributed within a narrow
range $\lambda_{\rm Edd} \sim 0.01 - 0.2$; (ii) the normalized jet power
$P_{\rm j}/L_{\rm Edd}$ formally correlates with the accretion rate
$\lambda_{\rm Edd}$, with some saturation at the largest values $\lambda_{\rm
Edd}> 0.05$; (iii) the jet production efficiency $\eta_{\rm jet} \equiv P_{\rm
j}/\dot{M}_{\rm acc} c^2$ spans a range from $\eta_{\rm jet} \lesssim 10^{-3}$
up to $\sim 0.2$ at maximum, which is below the level expected for magnetically
arrested disks around maximally spinning black holes; and (iv) there is a
diversification in $\eta_{\rm jet}$ on the hardness--intensity diagram $L_{\rm
X}/L_{\rm bol} - \lambda_{\rm Edd}$, with the jets being produced most
efficiently during the high/hard states, and suppressed during the soft states.
