  In this paper, we present for the first time comprehensive and detailed
results on the correspondence between the extrapolated deep inelastic structure
function $g_1$ of both the proton and the neutron with the same quantity
measured in the nucleon resonance region. We use a QCD parameterization of the
world data on DIS spin structure functions, extrapolated into the nucleon
resonance region and averaged over various intervals in the scaling variable
$x$. We compare the results with the large data set collected in the
quark-hadron transition region by the CLAS collaboration, averaged over the
same intervals. We present this comparison as a function of the momentum
transfer $Q^2$. We find that, depending on the averaging interval and the
minimum momentum transfer chosen, a clear transition to quark-hadron duality
can be observed in both nucleon species. Furthermore, we show, for the first
time, the scaling behavior of $g_1$ measured in the resonance region at
sufficiently high momentum transfer. Our results can be used to quantify the
deviations from the applicability of pQCD for data taken at moderate energies,
and help with extraction of quark distribution functions from such data.
