For a better understanding of the socio-economic dynamics in the sierra-coast region socio-economic territorial units were first defined through methodologies used in economic geography (Propin and Sanchez 1998; Sanchez et al., 1999; Juarez 2000; Cardona 2004).
El metodo de tipificacion probabilistica ha sido desarrollado ampliamente por Propin y Thurmer (1986), Reyes (1997 y 2000), Propin y Sanchez (1998a y 1998b), Vazquez (2000), entre muchos otros.