Thus, the retirement would be calculated automatically by the formula: Sb = M x f Where: Sb = benefit wage; M = average of 80% bigger wages of contribution of the insured, refined between July of 1994 and the moment of the retirement, corrected monetarily; f = previdencirio factor. The approved previdencirio factor is gotten by intermediary of the following formula: Where: f = previdencirio factor; Id = age of the contributor at the moment of the retirement (id); You are = life expectancy; tc = contribution time; = aliquot in the value of 0,31, referring to the contribution of 11% of the employee more of 20% of the employer. Pparently the creation of the previdencirio factor certain sample rationality, also shows to a set of contradictions of the proper factor and certainly many questionings on the concrete impacts of its application to the long ones of the years that if had followed to its creation. 3,2 FRAGILITIES AND CONTRADICTIONS OF THE FORMULA OF THE FACTOR In agreement PREVIDENCIRIO DIEESE (2008), in what it says respect to the formula of the previdencirio factor, must be given the attention in two aspects of the model: the first one is the endogenous tax of interests foreseen and as it is the life expectancy as determinative element in the definition of the factor. DIEESE (2008) concludes that the implicit tax of interests increases when the age at the moment of the retirement increases. Therefore, when considering two workers with the same time of contribution and different ages, oldest would be benefited with a bigger tax of interests, what he would happen on its previdencirias contributions as if was deep a proper one where they would leave the resources to finance its retirement until its death. TABLE 2 DIEESE (2008) explains through examples of financial applications that the implicit taxes of annual real interests in the previdencirio factor are very on this side. .