  We construct a language for identifying kinematical regions of transversely
differential semi-inclusive deep inelastic scattering cross sections with
particular underlying partonic pictures, especially in regions of moderate to
low $Q$ where sensitivity to kinematical effects outside the usual very high
energy limit becomes non-trivial. The partonic pictures map to power law
expansions whose leading contributions ultimately lead to well-known QCD
factorization theorems. We propose methods for estimating the consistency of
any particular region of overall hadronic kinematics with the kinematics of a
given underlying partonic picture. The basic setup of kinematics of
semi-inclusive deep inelastic scattering is also reviewed in some detail.
