  Conceptually, radii are amongst the simplest Poincar\'e-invariant properties
that can be associated with hadrons and light nuclei. Accurate values of these
quantities are necessary so that one may judge the character of putative
solutions to the strong interaction problem within the Standard Model. However,
limiting their ability to serve in this role, recent measurements and new
analyses of older data have revealed uncertainties and imprecisions in the
radii of the proton, pion, kaon, and deuteron. In the context of radius
measurement using electron + hadron elastic scattering, the past decade has
shown that reliable extraction requires complete elimination of bias associated
with practitioner-dependent choices of data fitting functions. Different
answers to that challenge have been offered; and this perspective describes the
statistical Schlessinger point method (SPM), in unifying applications to
proton, pion, kaon, and deuteron radii. Grounded in analytic function theory,
independent of assumptions about underlying dynamics, free from
practitioner-induced bias, and applicable in the same form to diverse systems
and observables, the SPM returns an objective expression of the information
contained in any data under consideration. Its robust nature and versatility
make it suitable for use in many branches of experiment and theory.
