A term referring to the understanding that when a society invests in girls, the effects are deep for the girls, multiple for society and a driver of sustainable development. According to an essay by the president of the Nike Foundation in UNICEF’s State of the World’s Children 2011, “When a girl in the developing world receives seven or more years of education, she marries four years later. An extra year of primary school boosts girls’ eventual wages by 10 to 20 per cent. Studies in 2003 showed that when women and girls earn income, they reinvest 90 per cent of it into their families, as compared to the 30 to 40 per cent that men and boys contribute. Research has also shown that higher levels of schooling among mothers correlate with better infant and child health.”