The United States is the most powerful colossus in the history of the world: Our nuclear warheads could wipe out the globe, our enemies tweet on iPhones, and kids worldwide bop to Beyoncé.

Yet let’s get real. All this hasn’t benefited all Americans. A newly released global index finds that America falls short, along with other powerful countries, on what matters most: assuring a high quality of life for ordinary citizens.

The Social Progress Index for 2015 ranks the United States 16th in the world. We may thump our chests and boast that we’re No. 1, and in some ways we are. But, in important ways, we lag.

The index ranks the United States 30th in life expectancy, 38th in saving children’s lives, and a humiliating 55th in women surviving childbirth. O.K., we know that we have a high homicide rate, but we’re at risk in other ways as well. We have higher traffic fatality rates than 37 other countries, and higher suicide rates than 80.