NEXT year China will overtake Japan to become the world's second-largest economy. Its rapid ascent has led some to question whether China will follow in Japan's footsteps, with the bursting of a massive bubble followed by years of decline. But China is still far poorer than Japan was at its peak, and thus has more room to improve productivity. A transition of surplus labour from agriculture to industry and services would increase efficiency and bring its economy more in line with the developed world. And China's stimulus package has produced much needed infrastructure that will reinforce future growth. But in the long run, a shift away from investment and exports towards domestic consumption would make China's output more sustainable, and help it to avoid experiencing a bubble like Japan's.