IDENTIFICATION AND ESTIMATION OF COMPLEX MULTIVARIATE LAG STRUCTURES - A NESTING APPROACH

A process for investigating complex and multivariate lag structures is proposed. The sources of the dynamic promotional effects on sales are explained and related to conventional means of mathematical expression. Multivariate and hybrid versions of the expressions are proposed and nests of equations are derived. The nests are not universal, so depend upon the subject selection of final models. The process is finally followed using an example from the pharmaceutical industry where both promotions and detailing are in use.