Strong surface inversion usually leads to deceptive Hall measurements by reflecting typical n-type behaviour for p-type samples, especially at low acceptor concentrations. A two-layer model is presented which can potentially be used to separate the bulk semiconducting properties from those of the surface layer. We here apply this model to two materials, InAs and InAsSb, and extract their transport properties. (c) 2006 Elsevier B.V. All rights reserved.