The second option is to predict a macro-variable gender differences using only individual-levels factors xt to estimate equation 2 for each country separately. It allows for country-specific variation in the gender happiness gap, considered as a societal effect that could vary according to the country and its definition of gender roles. It assumes the gender happiness gap being related to sociological construction rather than a biological effect associated with sex differences that would have involved a similar difference across countries. In particular, the collection of information on gender-based discrimination in social institutions is recent, and as such the SIGI is only available in one wave, thus limiting our empirical study to a cross-country analysis.