Nash bargaining model of HMO premiums

This paper estimates a model of commercial HMO premiums based on Nash's axiomatic approach to bargaining between HMOs and employers. The bargaining models incorporate variables that measure the 'power' of the parties to affect the division of potential gains from a contract. It is found that an increase in the number of competing HMOs increases the employer's bargaining power and leads to lower premiums, especially for for-profit HMOs. It is also found that employers' bargaining power over non-profit HMOs is positively related to the ratio of the HMO's administrative expenses/total expenses.

Learning by Accident? Reductions in the Risk of Unplanned Outages in U.S. Nuclear Power Plants after Three Mile Island.

This study uses a Cox proportional hazards model to analyze changes in the risk of unplanned outages in U.S. nuclear power plants after the Three Mile Island (TMI) accident. The unplanned outage hazard is related to safety by the fact that most such outages begin with unplanned reactor scrams. These place extreme stresses on plant equipment, increasing the risk of serious accident. The estimates indicate that the Nuclear Regulatory Commission (NRC)-led efforts to improve nuclear plant safety after TMI were followed by substantial reductions in the risk of unplanned outages