Introduction: The need to rethink approaches to population forecasts

Three major groups call on demographers to produce medium- and long-term population forecasts at the national, regional, or global levels - or produce them themselves. They are: other scientists, government and international agencies, and the general public, including private industry. What these consumers of forecasts demand of demographers, or what demographers think that they should demand, has been changing. The types of forecasts demanded are changing, the relevant dimension of forecasts is expanding, and users are increasingly requiring that forecasts include an indication of the degree of uncertainty of the forecast. Because the demands placed on demographers for population forecasts have been changing, it is an appropriate time to rethink some of their basic aspects. In this volume we address what we see as key issues in population forecasting: in what dimensions and at what levels of disaggregation should forecasts be provided? (And, in particular, are the traditional dimensions of age and sex sufficient?) Should population forecasts take note of limits to population or interactions between population and other variables? And how should uncertainty be treated? We believe that, at least in part, these issues are driven by changes in what users of forecasts want from population forecasters. The reader will note that we have used the term "forecasts" rather than the more common "projections." Demographers claim to produce population "projections," which are correctly computed numerical outcomes of a specified algorithm whose form, initial values, and controlling parameters or transition values are specified by the analyst. By definition, a projection must be correct unless arithmetical or other errors are made. However, users of population projections require population "forecasts." Forecasts are what Donald Pittenger (1980) called a "population projection selected as a likely outcome." Thus although a demographer makes a "projection," the user employs it as a "forecast." Some demographers cling to the distinction and wash their hands of what users do with their "projections" or how they interpret them. But we think that this distinction between "projections" and "forecasts"is false because demographers present only one or a limited number of the many possible projections. On what basis do they choose the projection or set of projections? Surely, on the basis that they judge the projection (or central projection of a set of projections) to be the most likely to occur. This point was made almost 50 years ago by Harold Dorn: it is difficult to see why a demographer would present anything other than the most likely outcome as the preferred middle projection (Dorn 1950). Similarly, although users are told that high and low population forecast variants are not confidence intervals, they are often taken to be so by users. And why should they not? Why else would a high and low variant be reported unless the demographer thought that they indicated the highest numbers and lowest numbers that were possible, although not highly probable? For these reasons, we favor the term "forecast" over the term "projection" where there is any, even implicit, predictive intent

Remittances in the South Pacific

For more than a quarter of a century there has been substantial emigration from the smaller island states of the Pacific to metropolitan fringe states, mainly the USA, New Zealand and Australia. Migration reduced unemployment in island states and remittances have contributed to raised living standards. This paper provides a better understanding of the implications of remittances for economic and social development in the Pacific region. It discusses alternative explanations of remittances, estimates of the size of remittance flows, the impact of remittances on the home country, and policies that influence the flow of remittances Much of the empirical work in this paper is based on Tonga and Samoa, although the findings apply more generally to other Pacific island nations

Frontiers of Population Forecasting

Most users of demographic data in government and industry require population forecasts-soundly based information on future population trends at the local, national, or global level. In the eyes of the public this is a principal justification for the discipline of demography And increasingly, sophisticated users expect not a single "best guess" of a population trajectory - perhaps straddled by "high" and "low" variants - but a range of demographic futures with associated indications of uncertainty, or even formal confidence intervals. Or they may want full-fledged scenarios of the development of the demographic system in different economic or environmental circumstances. Many population agencies, on the other hand, continue to generate population "projections" by methods that have been virtually unchanged for decades, with no assessment of probability and often claiming no ambition to predict. It is time to reexamine the procedures of population forecasting and to respond to these emerging demands by users. The nine chapters in this volume take on this task. The key issues they address include: What population characteristics beyond the standard variables of age and sex should routinely enter population forecasts? When should forecasts take account of economic or environmental feedbacks? How is forecasting accuracy to be assessed and what is the past record? What is the state of the art of stochastic time series modeling of population change? How can users cope with probability distributions? What scope is there for application of methods to incorporate expert opinion into population forecasting? Recent years have seen substantial advances in forecasting methods. These are beginning to be applied in population. For end users of forecasts who are familiar mainly with UN or similar population projection series and for the many professional demographers whose knowledge of projections has not progressed much since graduate, school, this volume opens a window on significant new developments in this field

Ways to improve population forecasting: What should be done differently in the future?

To improve population forecasting in the future, demographers should conduct more thorough assessments of the accuracy of past projections. Research should also focus on making greater use of: (1) models that include marriage, divorce, cohabitation, morbidity, and other demographic events that influence fertility, mortality, and migration as well as models that break populations down by educational achievement, employment status, and other variables; (2) models that take account of economic, social, and environmental dynamics, including integrated structural models and models with constraints; and (3) forecasting approaches that systematically quantify uncertainty. A further area that requires rethinking is the appropriate use of expert judgment in population projections. Finally, new ways need to be developed for distributing software for making population forecasts and for disseminating the results of alternative forecasts

Migrants' intentions to return home and capital transfers: A study of Tongans and Samoans in Australia

This article examines the attributes of migrants from the Pacific island states of Tonga and Samoa living in Australia to assess the extent to which return migrants could contribute to the human and physical capital stock of the migrant-sending countries. It also examines the impact of intention to return on remittances and asset accumulation. The study finds that very few migrants plan to return home and very little evidence that those who plan to return embody significant human capital (education, experience and skills). Intention to return may be important, nevertheless, since those who plan to return remit significantly more than those that do not and also accumulate far more physical capital at home than those that do not intend to return.