How much should we expect monetary integration to reduce differences among participating economies? Using data for the 50 U.S. states over 1929–1999, the paper finds that large differences across states persist in both business-cycle variability and correlations of state income with the U.S. as a whole. It is also shown that about a third of a state’s business-cycle volatility is explained by i...

When procurement takes place in the presence of horizontally differentiated contractors, the design of the object being procured affects the resulting degree of competition. This paper highlights the interaction between the optimal procurement mechanism and the design choice. Contrary to conventional wisdom, the sponsor’s design choice, instead of homogenizing the market to generate competition...

A large fraction of the world's species diversity is of recent evolutionary origin, and has evolved as a by-product of divergent adaptation in heterogeneous environments. Recent research provides a dire warning that homogenizing environments may cause the rapid loss of such species through a reversal of the speciation process.

Survey data are often used for comparison purposes, such as comparisons across nations or comparisons over time. To be effective, this would require equivalent questions and equivalent responses options to the questions. Yet there is a lot of variation in the response scales used, which, for example, differ in the number of response options used and the labeling of these options. This is the ca...