Motivated by a lack of Engel flexibility in commonly used demand systems, Rimmer and Powell developed a new demand system. This system, referred to AIDADS, is implicitly, directly additive, possesses marginal budget shares and thus Engel elasticities, that vary nonlinearly with expenditure such...

A recently developed demand system, nicknamed AIDADS (An Implicit, Directly Additive Demand System), offers an approach to capturing consumer preferences across a wide range of expenditure levels. AIDADS generalizes the LES by assuming marginal budget shares vary with utility and hence with...