Programme Evaluation with Unobserved Heterogeneity and Selective Implementation: The Mexican PROGRESA Impact on Child Nutrition

This paper considers the impact of Programa de Educación, Salud y Alimentación ( PROGRESA ), a large Mexican rural anti-poverty programme that had an evaluation sample in which overall treatment was randomly assigned to some communities but not others, on child nutrition. When we examine the impact of PROGRESA based on the presumption of randomized allocations, we find that PROGRESA had no or even a negative impact on child nutrition. However, not all children designated to receive nutritional supplements actually did so. Our preferred estimates – child fixed-effects estimates that control for unobserved heterogeneity that is correlated with access to the supplement – indicate a significantly positive and fairly substantial programme effect of the nutritional supplements on children 12–36 months. They imply an increase of about a sixth in mean growth per year for these children and a lower probability of stunting. Effects are somewhat larger for children from poorer communities but whose mothers are functionally literate. The long-term consequences of these improvements are non-trivial; its impact working through adult height alone could result in a 2.9% increase in lifetime earnings.     

LIQUIDITY AND THE INFORMATIONAL EFFICIENCY OF AFRICAN STOCK MARKETS

The hypothesis that a stock market price index follows a random walk is tested for 11 African stock markets, Botswana, Côte d'Ivoire, Egypt, Ghana, Kenya, Mauritius, Morocco, Nigeria, South Africa, Tunisia and Zimbabwe using joint variance ratio tests with finite-sample critical values, over the period beginning in January 2000 and ending in September 2006. The iid random walk hypothesis is rejected in all 11 markets. In four stock markets, Egypt, Nigeria, Tunisia and South Africa, weekly returns are a martingale difference sequence. Liquidity is an important factor which contributes to whether a stock market follows a random walk.     

Technical Efficiency Estimates of Scottish Agriculture: A Note

Within the UK there has been a lack of studies of technical efficiency at the Scottish level. This note compares the results obtained using Scottish data with a recent study by Hadley [Journal of Agricultural Economics (2006) Vol. 57, pp. 81–100] for English and Welsh farms. Four major sectors are investigated, namely: (i) cereals, (ii) dairy, (iii) sheep and (iv) beef over the period 1989 to 2004. Some distinct differences in efficiencies, returns to scale and causes of efficiency are found.     

The colors of investors’ money: The role of institutional investors around the world

We study the role of institutional investors around the world using a comprehensive data set of equity holdings from 27 countries. We find that all institutional investors have a strong preference for the stock of large firms and firms with good governance, while foreign institutions tend to overweight firms that are cross-listed in the U.S. and members of the Morgan Stanley Capital International World Index. Firms with higher ownership by foreign and independent institutions have higher firm valuations, better operating performance, and lower capital expenditures. Our results indicate that foreign and independent institutions, with potentially fewer business ties to firms, are involved in monitoring corporations worldwide.     

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.     

Advertising,Price and Quality in Self–regulating Professions: A Survey

This paper surveys the theoretical and empirical literature on the relationship between advertising, fees and quality in the self–regulating professions. Much of the literature is derived from the perspective of advertising as an information–enhancing device, helping to reduce the information asymmetry between professional and client. This is consistent with the majority of the empirical studies which suggest that advertising tends to have a downward effect on professional fees, with little if any adverse effect on quality. There are, however, important issues of method and measurement which may lessen the force of this conclusion     

An Economic Analysis of the UK Landfill Permits Scheme

The UK will introduce in 2004 a system of tradable permits for the landfill of municipal waste, in response to an EU directive setting limits on such activity. Tradable permits are becoming an increasingly popular method of dealing with some environmental issues — for example, sulphur dioxide (SO2) emissions in the USA. This paper describes the background to the landfill proposals and provides an analysis of how the permit system might work. Estimates are made of the possible savings in compliance costs of a permit system compared with a conventional ‘command–and–control’ approach. These estimates are subject to a considerable degree of uncertainty, related to factors discussed in the paper.     

Markets and pro-poor agricultural growth: insights from livelihood and informal rural economy models in Malawi

This article presents the development of a set of programming models describing the major features of different rural livelihoods and of the informal rural economy they together make up in Malawi. The models allow for differentiated responses by different household types to change and for the partial equilibrium effects of consequent supply, demand, and price adjustments in labor and grain markets. The models provide insights into the relations between own‐farm and nonown‐farm activities in different households' livelihoods and in the informal rural economy as a whole, and are used to investigate possible impacts of increasing cash crop prices and of a more open rural economy. Impacts of these changes on the poor are found to be critically dependent upon supply and demand elasticities in labor and grain markets, but the poor could potentially suffer significant losses from increased openness of the local economy leading to increased expenditure by less poor households on imported goods and services.     

Intertemporal Equity and Hartwick's Rule in an Exhaustible Resource Model*

In a standard exhaustible resource model, it is known that if, along a competitive path, investment in the augmentable capital good equals the rents on the exhaustible resource (known as Hartwick's rule), then the path is equitable in the sense that the consumption level is constant over time. In this paper, we show the converse of this result: if a competitive path is equitable, then it must satisfy Hartwick's rule.