正式保险对非正式风险分担机制的挤出效应--一个实验研究

The Crowding out of Formal Insurance on Informal Risk-sharing Mechanisms;An Experimental Study

推广正式保险往往被认为能够增加目标人群的福利。然而,本文在理论上证明,在异质性风险下,正式保险的引入常常会使得风险覆盖度变小而降低福利。这是因为先前存在的非正式风险分担机制可能会被过度挤出。为了避免实际中保险被引入的内生性问题,我们设计了一个实验来研究挤出效应和福利变化。我们观察到明显的挤出效应,但并不存在如理论所预测的过度挤出和风险覆盖率下降。然而,我们也发现挤出效应的大小和收入差距相关。收入差距过大会导致挤出过大而风险覆盖率不变。这使得引入正式保险的政策并没有产生预期的效果。这些发现为政策制定提供了一定的依据。

An important issue with promoting formal insurance in the developing countries that has been previ- ously ignored is the interaction between formal insurance and preexisting informal risk sharing arrangements. This paper shows, in theory, that introducing formal insurance to the underdeveloped areas often leads to a low- er degree of total coverage of heterogeneous risk, because formal insurance often crowds out preexisting informal risk -sharing arrangements in a more than one -for- one manner. Our laboratory experiment suggests that the crowding- out effect exists, but it is not more than one -for- one. However, we find that income inequality leads to larger crowding - out effect that significantly limits the positive welfare impact of introducing formal in- surance.