The absolute Raman intensities of all fundamental bands of CH3I, CH2DI, CHD2I and CD3I, previously reported, are used to obtain the derivatives of the molecular polarizability with respect to the symmetry coordinates. Special attention is paid to anisotropic scattering, and the influence of data from the high-resolution spectra is discussed both from theoretical and practical points of view. The bond-polarizability model is used for interpreting the derived Raman intensity parameters ∂α/∂Si. While for trace scattering the results are consistent, we have found that the ratio between diagonal and non-diagonal components of ∂α/∂Siis not reproduced well by the model.