Preference Function (PPF) approach. Empirical results based on this method (e.g. Sarris and Freebairn, 1983; [...] individuals in the favored group. A different approach, based on Olson (1965), Peltzman (1976) and Becker (1983) [...] each ATS transferred (DWL/(∆PSF + ∆PSI + ∆PSA)). Based on these results the political power of each group