The solution method, called Adjusted Winner, grew out of a mathematical proof in 1995 of a problem familiar to parents: how to divide a cake fairly between three or more people.
The theory behind the system, described today in New Scientist magazine, is that the two participants should feel that their slice is as good as the other person's and perhaps better. "This capitalises on how people value things differently," said Professor Alan Taylor, a mathematician at Union College in Schenectady, New York, who devised the system with Steven Brams, a professor of political science at New York University. "Both can walk away feeling that they have got up to two-thirds of the settlement.
"The system takes much of the worry out of being an inept bargainer, by providing a guarantee of fairness," he said.
Crucially, the system means that only one item must be sold; everything else gets allocated, said Professor Taylor. An example involves Adam and Barbara, who are divorcing and must divide up their townhouse, holiday cottage and vintage car. Each has 100 points, to be secretly allocated as they wish. Adam, valuing the car most highly for its sentimental worth, might put 60 points on it, 25 points on the townhouse, and 15 on the cottage. Barbara might think the car worth only 25 points. The townhouse though represents security - worth 65 points to her, leaving 10 points for the cottage. In the initial allocation, Barbara gets the townhouse, while Adam gets the car and cottage, because he rated those most highly. But that makes the points value of Adam's haul greater than Barbara's.
Thus the cottage is taken off Adam's list, leaving him a 60-point settlement, while Barbara has 65 points' worth. By selling the cottage and allocating 60 per cent of the cash raised to Adam (worth nine points, by his estimate), and the rest to Barbara (worth four points to her), both end up with 69 points' worth of value . Because of their differing value systems, each feels they have gained more than two-thirds of the estate.
Julia Cole, of the marriage guidance organisation Relate, said: "I have some admiration for this. But in some households one partner pays the mortgage while the other pays for everyday items, so one person might feel that items completely belong to them."Reuse content