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.     

Oppression and resistance: the powerless and the future

Relations between rich and poor (across and within countries) appeared in some questions in Images; there were clear differences between what the powerful and the powerless hoped and expected from the future. This is compared with what actually happened and a deeper analysis is made of ‘power’ as an organizing concept. It turned out that the pessimism associated with powerlessness tended to make better predictions.     

Expenditure on different categories of meat in Greece: the influence of changing tastes

This paper employs a latent variable approach to isolate the effects of changing tastes on the share of total meat expenditure on different categories of meat products in Greece during the period 1965–1995. We find that changes in the relative expenditure on different categories of meat cannot be explained by changes in the relative prices of the different meat products and increased expenditure alone. For pork products in particular, the increase in the share of expenditure has been greater than would be expected as a result of the relative fall in their price. The increase can therefore be associated with changes in taste. This finding is of general interest to those conducting empirical research into consumer behaviour both in economies where there have been significant changes in patterns of food consumption, and where, as in the case of many less industrialised economies, rapid structural changes in food consumption patterns are still to come. It is also of importance to policy makers in assessing die effectiveness of advertising or promotional campaigns in influencing longer term changes in consumer preferences for different products.     

Optimal failure rates and penalty-bonus policies in the offshore petroleum sector

We characterize optimal time profiles of risk-reducing expenditures and wreck probabilities for petroleum platforms. The input to our analysis is the development of wreck cost, direct and imputed. Particular attention is paid to the question of how private companies deviating from socially optimal standards may be induced to comply with such standards by means of a) a time-variant penalty, b) a no-wreck bonus and c) a time-invariant penalty.     

Stepwise multi-criteria evaluation

In this article we show that quantitative methods for multi-criteria evaluation have three serious shortcomings. First, the addition of an alternative which has bad criterion scores may distort the comparison between other alternatives. Second, the addition of a criterion which does not differentiate between alternatives may distort the comparison between alternatives. Third, when a ranking of alternatives is derived from a multi-criteria evaluation, it suggests complete transitivity. It is shown that intransitivity may occur.Therefore a stepwise procedure is recommended. It involves the removal of all criteria which do not or hardly differentiate between the alternatives and a pairwise evaluation of alternatives.     

Current Issues in the Analysis of Commercial Real Estate

This paper identifies and discusses a number of current issues regarding our understanding of commercial real estate markets. These issues include: 1) accurate estimation of the quantity and location of our nation's commercial space; 2) an understanding of the linkage between the space and capital markets for commercial real estate; 3) identification of the macroeconomic factors that affect the rate of return on commercial property and whether local market factors also affect the rate of return; 4) problems associated with measuring the return characteristics of equity investments in commercial property (including measures of the diversification benefits and inflation-hedging abilities of this asset class); 5) a better understanding of rental markets, including good measures of changes in effective rents over time; and 6) examination of the rationale for ownership of commercial space by corporate users. This paper reviews recent research related to these questions and suggests future research that should prove to be fruitful.     

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.