 In this equation formula_2 is the reported well-being of individual formula_3 at time formula_4, and formula_5 is a vector of known variables, which include socio-demographic and socioeconomic characteristics.Happiness, well-being, or satisfaction with life, was seen as unmeasurable in classical and neo-classical economics.Van Praag was the first person who organized large surveys in order to explicitly measure welfare derived from income.