  We present a comprehensive new global QCD analysis of polarized inclusive
deep-inelastic scattering, including the latest high-precision data on
longitudinal and transverse polarization asymmetries from Jefferson Lab and
elsewhere. The analysis is performed using a new iterative Monte Carlo fitting
technique which generates stable fits to polarized parton distribution
functions (PDFs) with statistically rigorous uncertainties. Inclusion of the
Jefferson Lab data leads to a reduction in the PDF errors for the valence and
sea quarks, as well as in the gluon polarization uncertainty at $x \gtrsim
0.1$. The study also provides the first determination of the flavor-separated
twist-3 PDFs and the $d_2$ moment of the nucleon within a global PDF analysis.
