however it assumes that this date has no effect on female male migration then the exogeneity of female male migration flows per capita is rejected by the wuhausman test at the level finally the validity ie covcedaw eq and the relevance ie covcedaw sigi of this instrument are tested this instrument is significantly correlated with the endogenous variable as indicated by the first step of the iv estimations table moreover simple estimation of the sigi including additional controls and instruments result in a relatively high partial r finally the paper checks that instrumental regressions are not null with fstatistic higher than suggested by the rule of thumb stock and yogo