NONPARAMETRIC ANALYSIS OF PRODUCTION EFFICIENCY: DISCUSSION

Productivity Analysis,

User's guide to an early warning system for macroeconomic vulnerability in Latin American countries

The authors develop an early warning system for macroeconomic vulnerability for several Latin American countries, drawing on the work of Kaminsky, Lizondo, and Reinhart (1997) and Kaminsky (1988). They build a composite leading indicator that signals macroeconomic vulnerability, showing that, historically, crises tend to happen in certain"vulnerable"situations. Interested mainly in providing an operational tool, the authors use a different approach to the problem than Kaminsky did. First, they use fewer variables to generate the signals. Then, after the variables are aggregated, a signal is issued, depending on the behavior of the composite index. (Kaminsky's procedure was to generate signals with each variable and then aggregate them.) Their results are satisfactory both statistically and operationally. Statistically, Type I and II errors are smaller than those reported in previous papers. Operationally, this system of leading indicators is less costly to maintain, given fewer variables-which are widely available and reported with timeliness. The authors tested the models'out-of-sample predictive ability on crises that occurred after the first stage of their project was finished: Colombia (September 1998), Brazil (January 1999), and Ecuador (February 1999). In all cases the models correctly anticipated the speculative attacks. Moreover, Mexico's models, estimated with information available two years before the 1994 crisis, show that these signaling devices would have been useful for signaling the macroeconomic vulnerability before December 1994.Statistical&Mathematical Sciences,Economic Theory&Research,Environmental Economics&Policies,Educational Technology and Distance Education,Scientific Research&Science Parks,Environmental Economics&Policies,Economic Theory&Research,Educational Technology and Distance Education,Statistical&Mathematical Sciences,Geographical Information Systems

An Efficient generic algorithm for the generation of unlabelled cycles

In this report we combine two recent generation algorithms to obtain a new algorithm for the generation of unlabelled cycles. Sawada's algorithm lists all k-ary unlabelled cycles with fixed content, that is, the number of occurences of each symbol is fixed and given a priori. The other algorithm, by the authors, generates all multisets of objects with given total size n from any admissible unlabelled class A. By admissible we mean that the class can be specificied using atomic classes, disjoints unions, products, sequences, (multi)sets, etc. The resulting algorithm, which is the main contribution of this paper, generates all cycles of objects with given total size n from any admissible class A. Given the generic nature of the algorithm, it is suitable for inclusion in combinatorial libraries and for rapid prototyping. The new algorithm incurs constant amortized time per generated cycle, the constant only depending in the class A to which the objects in the cycle belong.Postprint (published version

The Role of Promotion Programs for U.S. Poultry Exports

This study examines the effectiveness of price versus nonprice promotion programs for U.S. poultry exports. A comparative static simulation framework is specified for this purpose. The elasticities needed for the simulation model are estimated using seemingly unrelated regression and time-varying parameter regression techniques. Results from this study indicate that a price subsidy is more effective than nonprice market promotion programs in raising export demand for U.S. poultry.International Relations/Trade,