新常态下内需拉动经济增长是否存在有效边界*

新常态下，中国如何维持经济中高速增长既是重点，也是难点。由于外需拉动型经济增长方式逐渐难以为继，扩大内需的重要性日益突出。然而，扩大内需真的是有效国策吗？投资和消费拉动经济增长，是否存在有效边界？基于此，本文通过构建面板门限模型，利用2012-2013年中国275个市级数据，对内需拉动经济增长是否存在有效边界问题进行了实证检验。研究结果显示：投资拉动经济增长确实存在有效边界，当投资率较低时，增加投资能够有效拉动经济增长，当投资率已经较高时，增加投资对经济增长的拉动作用将不再显著；消费拉动经济增长也存在有效边界，当投资效率较低时，增加消费会抑制经济增长，当投资效率足够高时，增加消费才能够有效拉动经济增长。\

ARE THERE EFFICIENT FRONTIERS OF DOMESTIC DEMAND-DRIVEN GROWTH IN THE NEW NORMAL

How to maintain the rapid growth of Chinese economy is important and difficult in the New Normal. Because external demand led economic growth is gradually unsustainable, expanding domestic demand is becoming more and more important. However, is expanding domestic demand really effective national policy? Are there efficient frontiers if consumption and investment have a prominent influence on economic growth? Based on these questions, this paper builds panel threshold model to empirically test the efficient frontiers of stimulating Chinese economic growth by boosting domestic demand from 2012 to 2013 by 275 urban data. The results show that there are efficient frontiers of investment driven growth, increasing investment will effectively stimulate economic growth when investment rate is low, but increasing investment has no effect on economic growth when investment rate is high. Furthermore, we find that there are efficient frontiers of consumption driven growth, increasing consumption will inhibit economic growth when investment efficiency is low, but increasing consumption will promote economic growth when investment efficiency is high.