Knowledge that Transforms

The Malthusian model of population and economic growth has two key components. First, there is a positive effect of the standard of living on the growth rate of population, resulting either from a purely biological effect of consumption on birth and death rates, or a behavioral response on the part of potential parents to their economic circumstances. Second, because of the existence of some fixed resource such as land, there is a negative feedback from the size of population to the standard of living. These two components generate a number of predictions. Specifically, in the absence of technological change or expansion in the stock of the fixed resource, population will be stable around a constant level. Second, without changes in the function generating population growth, technological improvements or increases in the stock of resources will eventually result in more people but not a higher standard of living. As a description of population-income interactions, the Malthusian model had a long period of success, covering most of human history in most of the world until the beginning of the industrial revolution. In this paper we ask whether the model has any relevance to the world today. For the first part of the model—the positive causality running from income to population growth—the answer is clearly no. For reasons that have not fully been determined, countries that get richer now see falling rather than rising rates of population growth. Regarding the second part of the model—whether higher population lowers the standard of living—some further clarification is required before we can even pursue this issue. First, it important to differentiate among the different channels through which population affects economic outcomes. We will characterize as non-Malthusian those channels that work through the growth rate or demographic structure of the population. These include the effect of population growth in diluting capital per worker; the effect of the population age structure (itself a function of fertility) on the ratio of working age adults to dependents; the association of lower fertility with higher human capital investment via a quality-quantity mechanism; and the effect of lower fertility in freeing up female labor for output production. We reserve the term Malthusian for channels having to do with the size of the population, such as the congestion of fixed resources. This channel was the one Malthus thought about, and it is also the only one that pins down the level of population in steady state, which matches historical experience. Thus, in our typology, it is perfectly possible for reductions in population growth to raise income per capita even though the Malthusian channel is irrelevant. A second issue to be clarified is at what geographic scale we are looking. It is possible that in a world with trade, a high level of population in a single country will not lower that country’s income relative to others, but that a world with more people will be worse off because of congestion of productive resources or the environment. We do not pursue that possibility here. Instead, we ask whether there are countries or subnational regions in the world where the local version of Malthusianism hold true. The likeliest place to look for Malthusian effects is among poor countries, for several reasons. First, poor countries have had (and are continuing to have) the largest increases in population. The population of Africa is expected to multiply by a factor of 9.8 between 1950 and 2050. In India, during the century of most rapid population growth (1920–2020) population is expected to multiply by a factor of 5.5. By contrast, in Europe over the period 1800–1900 (roughly the century of fastest population growth), population increased by a factor of 2.2. If the initial population in these regions represented some equilibrium in the relation between population and resources (given available technology), the more rapid population growth is more likely to result in a disequilibrium in this relationship. Second, poor countries are least able to use trade as a means of avoiding resource constraints. Finally, as discussed further below, poor countries empirically have much higher shares of natural resource rents in national income than do rich countries. The idea that poor countries might suffer negative economic effects from overpopulation has a long pedigree. However, in recent decades, the Malthusian perspective has fallen out of favor among development economists, who have stressed the substitutability of technology, capital, and labor for fixed factors, as well as the productive benefits of density per se or of the technological and institutional changes induced by population pressure (see Allen C. Kelley 2001). We take as an operative test of the Malthusian channel the answer to the question: if a country had fewer people but was otherwise unchanged in terms institutions, human and physical capital per capita, productivity, terms of trade, etc., would it be significantly better off in per capita terms?

A Theory of Brain Drain and Public Funding for Higher Education in the United States by Felicia Ionescu and Linnea A. Polgreen. Published in volume 99, issue 2, pages 517-21 of American Economic Review, May 2009

In the public sector, employment may be inefficiently high because of patronage, and wages may be inefficiently high because of public employee interest groups. This paper explores whether the initiative process, a direct democracy institution of growing importance, ameliorates these political economy problems. In a sample of 650+ cities, I find that when public employees cannot bargain collectively and patronage could be a problem, initiatives appear to cut employment but not wages. When public employees bargain collectively, driving up wages, the initiative appears to cut wages but not employment. The employment-cutting result is robust; the wage-cutting result survives some but not all robustness tests. (JEL D72, J31, J45, J52)

South Africa's Post-apartheid Two-Step: Social Demands versus Macro Stability by Brahima Coulibaly and Trevon D. Logan. Published in volume 99, issue 2, pages 275-81 of American Economic Review, May 2009

The structure of employment is always changing, and economists are always trying to understand those changes. In the 1990s the idea of skill-biased technological change (SBTC) was used to understand the shift in employment toward more educated workers (see David H. Autor and Lawrence F. Katz 1999, for a survey). However, in recent years, it has become appar ent that a more nuanced approach is needed. The idea of SBTC might lead one to predict a uni form shift in employment away from low-skilled and toward high-skilled occupations, but studies for the United States (Autor, Katz, and Melissa S. Kearney 2006) and the United Kingdom (Goos and Manning 2007) have shown that there is growth in employment in both the high est-skilled (professional and managerial) and lowest-skilled (personal services) occupations, with declining employment in the middle of the distribution (manufacturing and office jobs). This is what Goos and Manning (2007) term job polarization (although see the introduc to Goos and Manning 2007 for antecedents of these ideas). There are several hypotheses about the rea sons for job polarization. First, the routiniza tion hypothesis (first put forward by Autor, Frank Levy, and Richard Murnane 2003) sug gests that the effect of technological progress is to replace routine labor which tends to be clerical and craft jobs in the middle of the wage distribution. Second, there is the view that globalization in general, and offshoring in par ticular, is an important source of change in the job structure in the richest countries (see, for example, Alan S. Blinder 2007). Third, there may be a link between job polarization and

January 2009Although almost half of the world™s population lives under nondemocratic regimes, thequestions of how policy decisions are made and how power changes hands in nondemocra-cies have received relatively little attention in the political economy literature. A popularview, forcefully articulated by Gordon Tullock (1987), is that because there are no stronginstitutions ensuring consensus and regulating the election and succession of leaders, non-democratic regimes rapidly degenerate into personal rule, where a single dictator dominatesevery aspect of decision-making. Tullock writes: fiEmpirically the Junta characteristicallyshrinks to one man...fl(p. 144) and continues to explain this as the result of dynamic in-teractions among the members of the junta. He suggests that there will typically be anaccumulation of power by one of the junta members. If this upstart member succeeds, hebecomes the sole ruler. If he fails, he is eliminated by the other members of the junta.This process continues until one member is standing. Tullock thus concludes: fiIt can beseen that this process would tend over time to lead the junta into becoming just one manthrough the gradual exclusion of individuals who had failed in plotting or the success of anindividual who had not.fl(p. 145)Tullock™s account, like that of many others, implicitly recognizes that politics in non-democratic and weakly-institutionalized societies should be conceptualized as one of thedynamic coalition formationS there are no rules that ensure orderly transitions of powerand no checks against some members of the ruling coalition eliminating or sidelining others.However, formal models of dynamic coalition formation in nondemocratic societies have notbeen developed until recently.In this paper, we draw on our work on dynamic coalition formation (Daron Acemoglu,Georgy Egorov and Konstantin Sonin, 2008a) and investigate Tullock™s conjecture formally.1

We study a simple model of liquidity risk management in which a firm is subject to rollover risk. When a firm is unable to rollover its maturing bonds by issuing new bonds, it may have to seek more expensive sources of financing or even liquidate its assets, possibly at fire-sale prices. One way to reduce this risk is to hold excess cash reserves, which can be expensive in practice (Bengt Holmström and Jean Tirole 2000; 2001). In this paper, we focus on an alternative way of managing liquidity risk, through the optimal (dynamic) choice of the maturity structure of debt. Our analysis highlights one advantage of short-term financing. The firm, while in good financial health, can readjust its maturity structure more quickly in response to changes in its asset value. Ideally, the firm would secure long-term financing just prior to when its financial health may worsen. Through this strategy, the firm can secure financing for the longest continuous period possible without rollover failure, avoiding inefficient restructuring costs. Put differently, the objective of the firm with long-term assets is to maximize the effective maturity of its liabilities across several refinancing cycles, rather than to maximize the maturity of the current bonds outstanding.

In a market-based financial system, banking and capital market developments are inseparable, and funding conditions are closely tied to fluctuations in the leverage of market-based financial intermediaries. Offering a window on liquidity, the balance sheet growth of broker-dealers provides a sense of the availability of credit. Contractions of broker-dealer balance sheets have tended to precede declines in real economic growth, even before the current turmoil. For this reason, balance sheet quantities of market-based financial intermediaries are important macroeconomic state variables for the conduct of monetary policy.

Temperature and Income: Reconciling New Cross-Sectional and Panel Estimates by Melissa Dell, Benjamin F. Jones and Benjamin A. Olken. Published in volume 99, issue 2, pages 198-204 of American Economic Review, May 2009