 As a result, this model has become one of the most adapted in the market, rivalling the Wind & Cardozo model head-on.One of the problems with the nested approach “is that there is no clear-cut distinction between purchasing approaches, situational factors and demographics".Bonoma and Shapiro are aware of these overlaps and argue that the nested approach is intended to be used flexibly with a good deal of managerial judgment” (Webster, 2003).