The principal advances in Social Security models have happened in troubled socially and economically situations. The result of them is the nowadays system. Nevertheless, in the year 2005 the World Bank proposed to design an economic benefit for every citizen depending on his own situation. This kind of benefit has to be supported in an annual financial base, taking into accounts the demographic and economic situation of the country. It is possible to define this benefit as Basic Income. This new level of social protection implies a redesign of the basic and compulsory level of protection that every country has. Even more as the World Bank proposed to be financed by a pay as you go system.

The aim of this paper is to design a Basic Income for the citizen understood as a system and basic economic level that guarantees the vital expenses of all of them financed by a by a pay as you go system.

Into the Spanish population exist demographic and economic important differences and these have to be in mind on designing the Basic Income. It is necessary to analyze the vital daily needs : Food, housing, clothes, transport, etc. These factors are the key to found a differentiation of the economic assignment (Basic Income) so, the final benefit should be according to the own characteristics of every citizen / family.

The data for this paper is the public survey of familiar budgets, therefore we establish a methodology of inter-quarter regression that allows discrimination for determinate the different values/levels of Basic Income, all of them according to economic and familiar typology.