An important public policy aspect of catastrophes such as hurricanes, floods, earthquakes and terrorist actions is the effect of public disaster relief on the incentives of private firms and individuals to make prudent risk management decisions.  Typically, economists are most worried by the possibility that public disaster relief, however well intentioned, may make matters worse in the long term by undermining incentives for firms and individuals to select economically efficient levels of private insurance and loss mitigation. 

A useful way to think about this problem is to consider what optimal risk management and insurance decisions might look like in a world without public disaster relief, and compare these decisions with the decisions that are likely to be made in a world with public disaster relief.  Since consumers fully internalize the costs and benefits of risk management and insurance decisions in the former case, but do not in the latter, the prospect of public disaster relief reduces consumers’ demand for private insurance and incentivizes consumers to underinvest in loss mitigation.  This is a classic example of the so-called “moral hazard” problem.  Moral hazard refers to the tendency for insured consumers to change their behavior in ways that increase the probability and/or size of claims.  It is an important issue whenever risk sharing occurs and the price at which risk is transferred is distorted in some fashion; e.g., in the form of subsidized insurance provided after the fact by public entities such as FEMA.