Proton-proton elastic scattering experiments are now of sufficient number and quality below 8 MeV to tightly constrain almost all isovector phase shifts which are significantly sensitive to elastic scattering parameters. A study of the sensitivity of various experimental observables to small changes in the phase parameter indicates which experiments might be most profitable in further constraining the phase shifts. There exists drastic disagreement between the measurements of Aj at 7 MeV in a recent experiment and current phase shift solutions, and since reasonable variations of the phase parameters do not produce significant improvement in the fit, the suspicion of some normalization error in the experiment is raised.