The global economic recovery "remains on track," according to the International Monetary Fund, but other experts say advanced economies are in for a period of slow growth.
The IMF study is published as leaders from the G-20, the world's major economies, are gathering in Hamburg, Germany to discuss growth, trade and other issues. The global lender urges nations to "work together" on economic issues because "there is no time for standing still."
The study's authors say the U.S. economy hit a "soft patch" earlier this year, while some European and Asian economies grew a bit faster than expected, with an upturn in manufacturing and trade.
These experts also warn that weak productivity growth, uneven distribution of economic gains, and aging workforces, limit growth, particularly in advanced economies.
A separate study by Fitch Ratings says advanced economies are likely to grow at a rate below 2 percent over the next several years.
Fitch writes that while the U.S. average growth rate over many years is "just below 3 percent," the outlook is just 1.8 percent. The study's authors blame the aging of the workforce for the slow pace of expansion.