Hagerty, M.R.

happiness income effect country gdp /capita /capita nation veenhoven hagerty wealth theory model utility table column group easterlin increase estimate study reference diener adaptive expectations satisfaction coefficient effect sizes comparison effect size correlation change oishi reference groups kapteyn research scale expectation point growth 10- point scale survey reference group adaptive example period estimation trend figure happiness data result 21 countries vanpraag sample evidence indicators research utility models time series contrast table 1 level oswald netherland adaptation 1973-96 belgium slope person analysis happiness ratings utility theory germany vanderstadt medium journal 10- review people press gdp /person japan italy