  We revisit sidewise dispersion relations as a method to relate the nucleon
off-shell form factor to observable quantities, namely the meson-nucleon
scattering phase shifts. It is shown how for meson-nucleon scattering a
redefinition of the intermediate fields leaves the scattering amplitude
invariant, but changes the behavior of the off-shell form factor as expressed
through dispersion relations, thus showing representation dependence. We also
employ a coupled-channel unitary model to test the validity of approximations
concerning the influence of inelastic channels in the sidewise dispersion
relation method.
