According to new research from McKinsey & Co., it will take the United States until 2016 to replace the 7 million jobs that were lost during the 2008-09 recession. And to gain full employment—finding work for the unemployed and accommodating the 15 million Americans expected to enter the labor force this decade—the U.S. economy must create 21 million jobs by 2020.

A return to full employment will occur in only the "most optimistic job growth scenario," according to the McKinsey Global Institute's report, "An economy that works: Job creation and America's future."

"Progress on four dimensions will be essential for reviving the U.S. job creation machine," report authors say. Those dimensions are: developing the U.S. workforces' skill to better match what employers are looking for; expanding U.S. workers' share of global economic growth by attracting foreign investment and spurring exports; reviving the nation's spark by supporting emerging industries, ensuring more of them scale up in the United States, and reviving new business start-ups; and speeding up regulatory decision-making that blocks business expansion and new investment.