A method and a system for generating a digitally encoded electric signal which represents a real property index are disclosed. The system comprises (i) a data store into which is input real estate data comprising property data, price data and time of sale data representing historical real estate transactions in a predetermined real estate market; (ii) data manipulation means connected to the data store to manipulate the real estate data into groups of consecutive triples times based on the time of sale data; (iii) generation means connected to the data manipulation means to generate a transform function using the manipulated data with two time dummy variables corresponding to two consecutive time periods respectively bounded by a triple consecutive times; (iv) coefficient extraction means connected with the generation means to extract the coefficients of the two time dummy variables of the transform function for the two consecutive time periods; (v) adding means connected to the coefficient extraction means to add the two extracted coefficients to generate a transformed growth rate from the first to the last of the triple times, and (vi) reverse transfer function generation means connected to the adding means to generate the digitally encoded electric signal which represents the logarithmic growth rate by calculating the reverse transform of the transformed growth rate. The transform function is a logarithmic function and the reverse transform function is an anti-log function. (61) Addition to 585199