In the year 2000, the United Nations developed an ambitious plan to meet the needs of some of the world’s poorest people by setting out the Millennium Declaration. A year later, eight Millennium Development Goals, or MDGs, were established as part of the effort.

Among them was a goal that called for achieving universal primary education. Like the other MDG goals, it was an admirable one. But some experts wondered: What about other aspects of education, such as secondary and higher education? What about the quality of education as opposed to simply making it universal?

In fact, say researchers Alicia Ely Yamin and Sakiko Fukuda-Parr, the MDGs’ focus on primary education effectively relegated some other worthy educational goals to the back burner, where they received less support—and less funding. Likewise, the other MDGs—aimed at addressing problems including poverty and hunger, maternal health, and child health—while admirable, also had unintended effects of marginalizing some issues that weren’t specifically mentioned in the list.

“One of the powerful things about the MDGs is that they set very specific goals, like cutting the proportion of people living on less than a dollar a day by half, or reducing maternal mortality ratios by 75%,” said Fukuda-Parr. “These are all very important priorities and no one would disagree with them. But there are many other global goals that are important. So we need to ask, ‘What did the MDGs leave out?’ ”