  We analyze the Sivers asymmetry in both Drell-Yan (DY) production and
semi-inclusive deep inelastic scattering (SIDIS), while considering properly
defined transverse momentum dependent parton distribution and fragmentation
functions and their QCD evolution. After finding a universal non-perturbative
spin-independent Sudakov factor that can describe reasonably well the world's
data of SIDIS, DY lepton pair and $W/Z$ production in unpolarized scatterings,
we perform a global fitting of all the experimental data on the Sivers
asymmetry in SIDIS from HERMES, COMPASS and Jefferson Lab. Then we make
predictions for the asymmetry in DY lepton pair and $W$ boson production, which
could be compared to the future experimental data in order to test the sign
change of the Sivers function.
