  The formulas directly connecting parton distribution functions (PDFs) at the
leading (LO) and the next to leading (NLO) QCD orders are applied to both
unpolarized and polarized valence PDFs and produce improved LO results on these
quantities without exclusion from the analysis the data coming from the small
and moderate $Q^2$ region. It is shown that derived in this way and presented
in the paper improved LO parametrizations of the valence PDFs could be obtained
within the standard LO analysis by using only the data produced at very high
$Q^2$ values (that is hardly possible in reality) and they strongly differ from
the original LO parametrizations of these quantities, obtained by using the
most of data produced at small and moderate $Q^2$ values. It is argued that LO
results on PDFs can be significantly improved even if the respective NLO
results are still unavailable.
