UNITED NATIONS — When António Guterres was selected over seven female candidates to lead the United Nations, deflating hopes for a first woman secretary general, he promised that the organization would move more forcefully to honor its ideals of gender equality.

“Do not let us in the U.N. off the hook,” Mr. Guterres, a Portuguese statesman and longtime United Nations diplomat, said in pledging to change what he acknowledged was a male-dominated world, including within the far-flung reaches of a patriarchal United Nations system. “Keep our feet on the fire.”

The International Center for Research on Women, a Washington-based rights and advocacy group that advises the United Nations, has been seeking to do just that. It devised recommendations for measuring what progress Mr. Guterres has made in shaping a more feminist United Nations, and translated them into letter grades.

After 2017, his first year, Mr. Guterres got a C-plus. On Wednesday, the group issued the secretary general’s second-year grade. It was only marginally better: B-minus.