University of California Radiation Laboratory Report UCRL-7563-T

A phase shift analysis is an attempt to translate experimental measurements (observables) into well-determined scattering amplitudes, since these are the quantities that can be readily compared with theoretical predictions, In this sense, the phase shift analysis should contain as little theory as possible. The scattering amplitudes (or phase shifts) constitute an experimental statement, and the phase shift analysis should logically be done by the experimental groups who measure the observables