[en] We perform a detailed analysis on the scaling properties of the total γ^* p cross section, σ_γ^*_p. We write the cross section as a product of two functions W and V representing, respectively, the dynamical degrees of freedom and the contribution from the valence partons. Analyzing data from HERA and fixed target experiments, we find that V is independent of Q² and concentrated at large x, while W carries all the information on the Q² evolution of σ_γ^*_p. We define the reduced cross section σ_γ^*_p = W = σ_γ^*_p/V, and show that it is very close to a generalized homogeneous function. This property gives rise to geometric scaling for σ_γ^*_p, and it also explains the known geometric scaling of σ_γ^*_p at low x. As a consequence of our Ansatz, we also obtain a compact parameterization of a σ_γ^*_p describing all data above Q² = 1 GeV². (Author)