A further school of thought based on models of buyer behaviour sees business relationships as being essentially about a process of choice reduction (Sheth and Parvatiyar 2002). From the buyer's perspective, having excessive choice involves spending time and effort evaluating the competing alternative. Models of buyer behaviour have been developed to show how buyers reduce the total available set of products to a more manageable 'choice set', which typically may involve just five or six product that are evaluated in greater detail. A relationship is one way of managing this process of choice reduction-in other words, a buyer will initially confine their search to those suppliers with whom they have already established a satisfactory relationship.