On-Line Portfolio Selection Using Multiplicative Updates

We present an on-line investment algorithm that achieves almost the same wealth as the best constant-rebalanced portfolio determined in hindsight from the actual market outcomes. The algorithm employs a multiplicative update rule derived using a framework introduced by Kivinen and Warmuth. Our algorithm is very simple to implement and requires only constant storage and computing time per stock in each trading period. We tested the performance of our algorithm on real stock data from the New York Stock Exchange accumulated during a 22-year period. On these data, our algorithm clearly outperforms the best single stock as well as Cover's universal portfolio selection algorithm. We also present results for the situation in which the investor has access to additional "side information."     

Why Do Nations Trade (So Little)?

There is not nearly as much trade as standard models suggest there should be. Formal trade barriers and transport costs are too low to account for the difference. The pattern of missing trade has interesting variation across country pairs. These clues suggest the need for theoretical and eventually structural empirical work on the missing transactions costs. This paper reviews recent empirical findings and some promising research directions in search, predation and contract theory.     

Government Purchases, Government Transfers, and the Post-1970 Slowdown In U.S. Economic Growth

This article shows that the post-1970 slowdown in U.S. economic growth can be explained by a shift in fiscal policy away from government purchases and toward transfer payments. Two endogenous growth models that include government purchases and transfers imply a relationship between these variables and long-run growth. Empirically, the simultaneous decline in the fraction of output purchased by federal, state, and local governments and rise in transfer payments around 1970 dramatically overpredict the growth slowdown of the early 1970s. The growth rate is predicted to have risen in the absence of this change in fiscal policy.     

The nonequivalence of tariffs,import quotas,and voluntary export restraints

This paper compares the equilibrium levels of prices, imports, production and consumption under a tariff, an import quota, and a voluntary export restraint when each trade restriction is set so as to lead to the same quantity of imports. Competitive, domestic production monopoly, import monopoly, and export monopoly cases are examined. Voluntary export restraints are shown to have different effects than import quotas or tariffs, especially when some potential exporters remain outside the agreements.     

The George Washington University Forecast of Emerging Technologies: A Continuous Assessment of the Technology Revolution

A method is presented for the continuous assessment of major technological advances—the George Washington University (GWU) forecast of emerging technologies. Environmental scanning and trend analysis are used to identify emerging technologies (ETs), and a Delphi-type survey then asks a panel of authorities to estimate the year each advance will occur, its associated probability, the potential size of its market, and the nation that will lead each ET. Eighty-five prominent ETs have been identified and grouped into 12 fields: energy, environment, farming and food, computer hardware, computer software, communications, information services, manufacturing and robotics, materials, medicine, space, and transportation. Results are presented from four survey rounds covering the past 8 years, and they are compared longitudinally to estimate the range of variance. The data are also divided into three successive decades to provide scenarios portraying the unfolding waves of innovation that comprise the coming technology revolution.