The Role of Higher Twist in Determining Polarized Parton Densities from   DIS data
  Different methods to extract the polarized parton densities from the world polarized DIS data are considered. The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron $g_1$ structure functions are found to be non-negligible and important in the QCD analysis of the present experimental data. Their role in determining the polarized parton densities in the framework of the different approaches is discussed. 
E. Leader, A.V. Sidorov, D.B. Stamenov