The analysis called SANDDABS which has had a long history of use in consumer purchase behaviour (including brand switching) at MRCA and elsewhere, is given a constrained information theoretic characterization. This is made possible by recent developments in optimization and duality which are precise and general. That is, these developments generalize the classical relations between information theory and statistics as previously established in very precise forms by Khinchin-Kullback-Leibler (and others). Contacts with geometric programming in an extended form along with other recent developments in optimization and duality are also supplied and a way is thereby opened for unifying many apparently separate approaches to market analysis.