Killing off cohorts: Forecasting mortality of non-extinct cohorts with the penalized composite link model

Mortality forecasting has crucial implications for insurance and pension policies. A large amount of literature has proposed models to forecast mortality using cross-sectional (period) data instead of longitudinal (cohort) data. As a consequence, decisions are generally based on period life tables and summary measures such as period life expectancy, which reflect hypothetical mortality rather than the mortality actually experienced by a cohort. This study introduces a novel method to forecast cohort mortality and the cohort life expectancy of non-extinct cohorts. The intent is to complete the mortality profile of cohorts born up to 1960. The proposed method is based on the penalized composite link model for ungrouping data. The performance of the method is investigated using cohort mortality data retrieved from the Human Mortality Database for England & Wales, Sweden, and Switzerland for male and female populations.     

Influence of a high‐head dam as a dispersal barrier to fish community structure of the Upper Mississippi River

In river systems, high‐head dams may increase the distance‐decay of fish community similarity by creating nearly impermeable dispersal barriers to certain species from upstream reaches. Substantial evidence suggests that migratory species are impacted by dams, and most previous studies in stream/river networks have focused on small streams and headwaters. Here, we assess whether a high‐head dam (Lock and Dam 19; LD 19) on a large river, the Upper Mississippi River (UMR), substantially alters fish community structure relative to variability expected to occur independent of the dam's effect as a fish dispersal barrier. Using fish catch per unit effort data, we modelled the distance‐decay function for the UMR fish community and then estimated the similarity that would be expected to occur across LD19 and compared it with measured similarity. Measured similarity in the fish community above and below LD19 was close to the expected value based on the distance‐decay function, suggesting LD19 does not create an abrupt transition in the fish community. Although some migratory fish species no longer occur above LD19 (e.g., skipjack herring, Alosa chrysochloris), these species do not occur in high abundance below the dam and so do not drive variation in fish community structure. Instead, much of the variation in species structure is driven by the loss/gain of species across the latitudinal gradient. Lock and Dam 19 does not appear to be a clear transition point in the river's fish community, although it may function as a meaningful barrier for particular species (e.g., invasive species) and warrant future attention from a management perspective.     

Invertebrate response to impacts of water diversion and flow regulation in high‐altitude tropical streams

Water supply systems are critical infrastructure that provides food and energy security for developed societies. The operation of reservoirs (flow regulation) and water intakes (water diversion) has known negative impacts on aquatic ecosystems; however, quantification of ecological impacts and examination of these two types of flow alteration remain a developing area of research. We investigated the individual and combined impact of flow regulation and water diversion on stream ecosystem integrity, the freshwater macroinvertebrate community, and the population structure of flow‐sensitive insects. For 2 years, we monitored quarterly discharge, physical and chemical stream conditions, and benthic invertebrates of four high‐altitude tropical streams that are part of the water supply system of Quito, Ecuador. Flow regulation caused a loss of the hydrological seasonality of these streams, including a decrease in stream depth and biotic quality. Water diversion caused a decrease in dissolved oxygen and overall ecosystem integrity. Freshwater invertebrate density and richness decreased as a result of water diversion and flow regulation. The combined flow alteration in these streams decreased the density of nymphal stages of the widely distributed mayfly Andesiops peruvianus. Given the societal needs for food and energy security, water management for diversion (e.g., irrigation) and in‐line storage practices (e.g., hydroelectric dams) are anticipated to increase. This research suggests that the negative environmental impacts of flow alteration could be mitigated with discharge releases designed to approximate the natural hydrologic regime of undisturbed streams.     

Book Reviews

R.J. May and W.J. O'Malley (eds), Observing Change in Asia. Essays in Honour of J.A.C. Mackie, Bathurst: Crawford House Press, 1989, pp. 265. Paper: A$20.00.

Michael R. Dove (ed.), The Real and Imagined Role of Culture in Development: Case Studies from Indonesia, Honolulu: University of Hawaii Press, 1988. US$ 32.00.

Fukuo Ueno, Desa Cimahi: Analysis of a Village on Java during the Japanese Occupation (1943), Rotterdam: Comparative Asian Studies Programme (GASP), Erasmus University, 1988, pp. 291 + xi.

Sritua Arief and Adi Sasono, Modal Asing, Beban Hutang Luar Negeri dan Ekonomi Indonesia, Jakarta: LSP dan UI Press, 1987, pp. 69 + xix.

BRIEFLY NOTED: World Bank, World Debt Tables 1989–90, 2 Vols, Washington Dc, 1989.

Mohan Munasinghe, Energy Analysis and Policy, London: Butterworths, 1990, pp. 315 + xx; Electric Power Economics, London: Butterworths, 1990, pp. 323 + xviii.     

On the theory of macroeconomic policy

Summary Jan Tinbergen originated the theory of policy in the 1950s. Here I apply it to contemporary macroeconomics. The two standard instruments of short-run demand management cannot achieve the two usual targets, full employment and price stability. With respect to those goals, these two instruments are collinear, except for small and transient effects on foreign exchange rates. But the mix of fiscal and monetary policies, relative to one another, does have important effects on the composition of national output, as between investment and consumption.I point out that policy-makers, like portfolio managers, should diversify the instruments they use when they are uncertain of their effects. I discuss some pitfalls in the empirical estimation of policy effects, especially possible misinterpretations of simple correlations, and I note that policy rules cannot be invariant to changes in macroeconomic structure. I argue that policy rules should involve responses to new information and in practice allow discretion. Finally, I suggest that Tinbergen's theory of policy needs to be extended to policy coordination among nations.Third Tinbergen Lecture delivered on October 20, 1989, in Utrecht for the Royal Netherlands Economic Association.     

Discriminating Among Alternative Theories of the Multinational Enterprise

Recent theoretical developments have incorporated endogenous multinational firms into the general–equilibrium model of trade. One simple taxonomy separates the theory into "vertical" models, in which firms geographically separate activities by stages of production, and "horizontal" models, in which multiplant firms duplicate roughly the same activities in many countries. The authors nest a horizontal and a vertical model within a hybrid (unrestricted) "knowledge–capital model" and estimate the specifications with data on US foreign direct investment activity. In the nested econometric tests, the data sample cannot distinguish statistically between the unrestricted model and the restricted horizontal model, indicating that the latter captures virtually all of the determinants of FDI. The tests overwhelmingly reject the vertical model.     

Costly pollution abatement, competitiveness and plant location decisions

The NAFTA debate included assertions that were used as arguments against trade and investment liberalization. (1) Trade liberalization increases production sensitivity to environmental restrictions (‘environmental dumping’?). (2) Investment liberalization, leading to multinational firms, similarly increases the production and welfare response to costly environmental restrictions. I find that: (1) Trade liberalization increases production sensitivity to costly environmental restrictions, but arguments against liberal trade on welfare grounds do not follow. (2) Multinationals do not increase the production-reallocation effect caused by environmental restrictions or regulations. In addition, I find a great difference between restrictions that fall on fixed costs and restrictions that fall on marginal costs.     

The Productivity of US States since 1880

This study uses state-level variation in labor productivity levels at twenty-year intervals between 1880 and 1980 to examine the relative importance of institutional and geographical influences in explaining observed and persistent differences in standards of living over time and across regions. Focusing on fundamental rather than proximate influences, we find that both institutional characteristics and some physical geography characteristics account for a high proportion of the differences in state productivity levels: states with navigable waterways, a large minerals endowment, and no slaves in 1860, on average, had higher labor productivity levels throughout the sample period. However, we find little support for two other influences that have previously received attention—climate and latitude.     

国有企业、金融市场改革与养老保险制度改革的互动效应--中国如何解决老年保障问题?

中国政府非常清楚社会保障所面临的危机，决定寻求解决办法。拟议中的社会保障改革的核心是积累制和整合条块分割的体系，计划为每个工人建立个人退休账户，对养老基金进行有效投资。然而，这种改革受阻于三个关键因素。(1)在向积累制的转化过程中必须支付特制成本；(2)现有的社会保障体系条块分割、分散化管理3(3)已经积累的基金尚未取得高收益，也未分配到最有效率的用途上。