1. A method for estimating the values of a subject property and providing a quality measure of the estimated value, said method comprising the steps of: providing a generative system based on the combination of fuzzy logic systems and neural networks capable of accepting multiple inputs and providing a single output; retrieving data for multiple properties, the data for each property comprising multiple attributes and selling price of the property; training said generative system using the retrieved data, using said attribute information as inputs and adjusting said generative system to cause the output of the generative system to conform with the selling price of the property associated with the attribute information; providing attribute information regarding the subject party to said trained generative system; receiving the estimated value of the subject property from said trained generative system; and receiving the quality measure of the estimated value from said trained generative system.