Time Series Concepts for Conditional Distributions*

The paper asks the question – as time series analysis moves from consideration of conditional mean values and variances to unconditional distributions, do some of the familiar concepts devised for the first two moments continue to be helpful in the more general area? Most seem to generalize fairly easy, such as the concepts of breaks, seasonality, trends and regime switching. Forecasting is more difficult, as forecasts become distributions, as do forecast errors. Persistence can be defined and also common factors by using the idea of a copula. Aggregation is more difficult but causality and controllability can be defined. The study of the time series of quantiles becomes more relevant.     

Demographic and Economic Pressure on Emigration out of Africa*

Two of the main forces driving European emigration in the late nineteenth century were real wage gaps between sending and receiving regions and demographic booms in the low‐wage sending regions. Our new estimates of net migration for the countries of sub‐Saharan Africa show that exactly the same forces driving African across‐border migration are at work today. The results suggest that rapid growth in the cohort of potential young emigrants, population pressure on the resource base, and slow economic growth are likely to intensify the pressure for migration out of Africa and into high‐wage OECD countries over the next two decades.     

Ethical Outsourcing in UK Financial Services: Employee Rights

Outsourcing is becoming a major option in British business, including the financial services industry, and it raises a number of ethical considerations. The author of this major ethical study contends that "Outsourcing seems to present a particular threat to employees ... because of the factors which have led to outsourcing and the way in which it tends to work." Mike Henderson is an Associate of the Chartered Institute of Bankers and Senior Lecturer in Financial Services in the School of Financial Studies and Law of Sheffield Hallam University, City Campus, Pond Street, Sheffield S1 1WB, England.     

Price Competition When Consumersare Uncertain About Which Firm Sells Which Quality

In this paper we analyze the properties of price equilibria in a duopoly market where firms sell vertically differentiated products, consumers being uncertain about which firm sells which quality. Both existence and properties of price equilibria are characterized by the beliefs of the consumers' population about the distribution of quality between firms.     

Using an approximate kiefer-weiss solution for testing insect population densities

Summary A sequential testing procedure called 2-SPRT for the meanμ of the negative binomial distribution with known exponentk is presented. For any fixedμ ₀(μ ₁<μ ₀<μ ₂), the 2-SPRT provides an asymptotic solution to the modified Kiefer-Weiss problem. Determination ofμ ₀ such that the test provides an approximate solution to the Kiefer-Weiss problem is described. The behavior of the 2-SPRT and the Sequential Probability Ratio Test is investigated using Monte Carlo methods. The error probabilities and the average sample numbers are compared. All the computations were carried out on the Alabama Supercomputer.     

Action Teams That Work

A growing awareness of workplace hazards and identification of airborne contaminants, coupled with a changing safety and health regulatory environment, created an unexpected demand for new and innovative respirators in the early 1980s. 3M's Occupational Health and Environmental Safety Division broke new ground by taking the team concept further than ever before in the company. The division's Action Teams successfully designed, built and introduced products in less than half the time it would have taken previously. Robert Hershock, Charles Cowman and Douglas Peters describe how 3M learned important lessons about team selection, training, performance and motivation, the importance of project sponsors, and the role of middle management.     

Racial disparity in the atlanta housing market

Atlanta has the reputation of being a city of opportunity for blacks. However, in Atlanta, as well as in other cities across the nation, the nexus of racism and economic discrimination has resulted in disparities between the housing status of blacks and whites. This article examines racial disparities in the Atlanta housing market. It begins by tracing recent trends in the Atlanta-area economy and by providing background information on the local housing market. It then discusses the roles of the federal Home Mortgage Disclosure Act of 1975 and Community Reinvestment Act of 1977 in the efforts of local groups to reduce racial disparities in the housing market. The final section discusses recent local developments that might lead to improvements in the housing status of black Atlantans.     

The effects of mergers on price and output: Two case studies from the airline industry

The literature on industrial organization contains very little direct evidence on the effects of actual mergers. This study estimates the effects of two recent airline mergers approved by the Department of Transportation over the objection of the Department of Justice. The merger of TWA and Ozark appears to have caused a slight increase in fares and a far greater reduction in service on city pairs out of St Louis. The merger of Northwest and Republic appears to have caused a significant increase in fares and a significant reduction in overall service on city pairs out of Minneapolis-St Paul.