This paper considers tests of the parameter on endogenous variables in an instrumental variables regression model. The focus is on determining tests that have some optimal power properties. We start by considering a model with normally distributed errors and known error covariance matrix. We...

In the context of the TRIPS agreement and the accompanying debate about the merits of the requirement to enforce product patents for pharmaceuticals, this paper provides a rigorously-derived estimate of the possible impact of pharmaceutical product patents on prices and welfare in a developing...

The US airline industry went through tremendous turmoil in the early 2000s, with four major bankruptcies, two major mergers, and various changes in network structure. This paper presents a structural model of the industry, and estimates the impact of demand and supply changes on profitability....

In the past few decades multistore retailers, especially those with 100 or more stores, have experienced substantial growth. At the same time, there is widely reported public outcry over the impact of these chain stores on other retailers and local communities. This paper develops an empirical...

Under the TRIPS agreement, WTO members are required to enforce product patents for pharmaceuticals. The debate about the merits of this requirement has been and continues to be extremely contentious. Many poor developing economies claim that patent protection for pharmaceuticals will result in...