The formal analogy existing between problems studied in the microscopic theory of disordered alloys and problems concerned with the effective (macroscopic) behavior of heterogeneous materials is discussed. Attention is focused on 1) analogous approximations (effective medium approximations) developed for the microscopic problems by scattering theory concepts and techniques, but for the macroscopic problems principally by intuitive means, 2) the link, provided by scattering theory, of the intuitively developed approximations to a well‐defined perturbative analysis, 3) the possible presence of conditionally convergent integrals in effective medium approximations.