  This article presents a summary of overlapping presentations by the author to
the QCD Evolution 2013 Workshop and to the Opportunities for Polarized Physics
at Fermilab Workshop. It contains an introduction to the concept of
Kane-Pumplin-Repko (KPR) factorization and descibes how this concept can be
used in the analysis of high-precision measurements of parity-conserving
transverse single-spin asymmetries. The discussion demonstrates that such
measurements can not only probe directly for specific mechanisms that enhance
our fundamental understanding of nonperturbative QCD but, because transverse
spin asymmetries are unambiguously perameterized by a spin-directed momentum
shift, such measurements can also be used to calibrate other phenomenological
applications of transverse momentum dependent distributions (TMD's) and of TMD
evolution. The calibration supplied by these measurements can thus enable the
use of TMD factorization for the exploration of a broad range of other aspects
of hadronic structure.
