1. A method performed by an electronic data machine for grouping one or more retail store units of a first set of retail store units together based on common economics, said method comprising: a) generating at least one fixed price index using a computer for plurality of retail store units over a select period of time; b) identifying and storing a number of variables associated with each of the plurality retail store units, each variable having a standardized value; c) generating a regression coefficient for each of the identified variables by regressing profits against the at least one fixed price index and a product of the at least one fixed price index and the identified variables; and d) identifying which of the variables have more significant regression coefficient and outputting the identified variables; e) grouping one or more retail store units from said plurality of retail store units having these identified variables together as being in a common economic market using the computer.