A general analysis is presented of the sensitivity of reflectometry to perturbations of the plasma profile, using a full-wave description in one-dimension. The square of the wavenumber is allowed to have an imaginary part, to account for absorption or divergence of the wave. Correlation reflectometry is investigated. It is found that the phase correlation is substantial, regardless of the correlation length of the fluctuations, unless either the wave attenuation is substantial or else the fluctuation correlation function is non-monotonic, corresponding to narrow-band turbulence. Curves are presented that provide fairly general information for the purpose of experimental interpretation.