Second - considering participation in the programme as a random process - the Unconfoundedness Hypothesis assumes that non-observable characteristics are unable to affect not only the treatment assignment but also the potential outcomes. To do this, we adopt the propensity score, which defines the probability that a family would participate in the programme given a set of observable characteristics. The variables introduced in the regression are: household market income, the largest number of years of education within the household, the number of children (under 14 years old), plus three characteristics of the house (number of people per rooms, water supply and roof conditions) as the programme considers the housing dimension to be one of the most important elements in defining the level of well-being.