The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron $g_1$ structure functions are extracted from the world data on $g_1(x,Q^2)$ in a model independent way and found to be non-negligible. Their role in determining the polarized parton densities in the nucleon is discussed. It is also considered how the results are influenced by the recent JLab and HERMES/d inclusive DIS data.
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