The effectiveness of this method rests on one deceptively simple condition – the ability to define the success of a call. In most calls readers will need to demonstrate to customers that they have something worthwhile to offer. Most of us in larger sales are selling solutions to customer problems. In the demonstrating capability stage of the call, readers have to show customers that they have a solution and that it makes a worthwhile contribution to helping solve their problems. In larger sales, where only a small percentage of discussions with the customer result in an order or a no-sale, it becomes difficult to judge the success of individual calls. One of the attractions of dividing questions into open and closed is that the distinction seems very straightforward.