Interval constraint spreadsheets for financial planning

Spreadsheets are difficult to use in applications, where only incomplete or inexact data (e.g. intervals) are available-a typical situation in financial planning. The author argues that this is due to two fundamental shortcomings of the computational paradigm underlying spreadsheets: firstly, the distinction between input and output cells has to be fixed before computations; and secondly, cells may have only exact values. As a result, spreadsheets support the user only with primitive iterative problem solving schemes based on trial-and-error methods. He presents a constraint based computational paradigm for next generation interval spreadsheets. The scheme makes it possible to exploit incomplete/inexact data (intervals) and it can support problem solving in a top-down fashion. Current spreadsheets constitute a special case of the more general interval constraint spreadsheets proposed