The polarization change of a polarized neutron beam after transmission through a partly magnetized ferromagnetic material can be described by a (3 × 3) depoalarization matrix. An earlier interpretation of this matrix in terms of domain quantities such as the reduced mean magnetization m, the mean domain size δ and the mean square direction cosines γ x , γ y and γ z of the inner magnetization within the domain is extended by taking into account different correlations occuring in real domain structures, such as the correlation between neighbouring domain orientations expressed by the mean direction cosine K between these orientations and the correlation between the domain dimensions and the domain magnetization orientation of an arbitrary domain. The latter correlation can be expressed by means of the quantities Δ and I`, where Δ is a measure for the average shape anisotropy of the domains with respect to the direction of domain magnetization, and Γ is a measure for the movement of domain walls during the magnetization process of the sample. The possibilities and limitations of the resulting theory on neutron depolarization experiments are discussed.