The study looked at how changes in China's economy between 1952-1998 affected its growth. They found that China's efficiency in using resources improved over time, with technology from advanced countries helping boost productivity. By the late 1990s, the return on investment in China dropped significantly. This means that while labor became more important for growth, capital's contribution decreased. To keep growing, China needs to fix issues in how it allocates capital to make the most of its resources.