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PubMed1991

Analysis and prediction of the population in Spain: 1910-2000.

"The starting hypothesis of this paper was the actual occurrence of important interactions between demographic and socio-economic factors when trying to reach population forecasts that may be more efficient than those obtained by mere extrapolative methods. In order to be able to implement this approach to the Spanish case it has been necessary to reconstruct first the Spanish population series by age and sex groups from 1910 to 1980. Later, we proceed to obtain population forecasts using alternative modeling strategies and comment on the potential problems that the new demographic situation may have for future public policy."

Age Distribution↗
PubMed1991

The impact of forecasting methodology on the accuracy of national population forecasts: evidence from the Netherlands and Czechoslovakia.

"This study considers the accuracy of national population forecasts of the Netherlands and the Czechoslovak Socialist Republic.... We look at the demographic components employed in each forecast, the procedure to extrapolate fertility and the level at which assumptions for each component are formulated. Errors in total population size, fertility, mortality and foreign migration, and age structure are considered. We discuss trends in errors and methodology since 1950 and compare the situations in the two countries. The findings suggest that methodology has only a very limited impact on the accuracy of national population forecasts."

Czechoslovakia↗
PubMed1993

Forecast intervals of net migration: the case of the Netherlands.

This study addresses problems concerning the forecasting of net migration in the preparation of population forecasts. "As the width of forecast intervals for migration in single years differs strongly from that of an interval for average migration during the forecast period, it is important that the forecaster indicates which type of interval is presented. A comparison of forecast intervals for net migration obtained from an ARIMA model to intervals in official Dutch national population forecasts shows that the uncertainty on migration has been underestimated in past official forecasts."

Demography↗
PubMed2007

Behavioral differences between public and private not-for-profit hospitals in the Italian National Health Service.

In this paper we attempt to identify behavioral differences between public and private not-for-profit hospitals, by exploiting the introduction of the DRG-based payment system in the Italian NHS during the second half of the 1990s. We estimate the technical efficiency of a sample of hospitals for the period 1995-2000 considering an output distance function, and adopting both parametric (COLS and SF) and nonparametric (DEA) approaches. Our results show a convergence of mean efficiency scores between not-for-profit and public hospitals, and seem to suggest that differences in economic performances between competing ownership forms are more the result of the institutional settings in which they operate than the effect of the incentive structures embedded in the different proprietary forms. We also observe a decline in technical efficiency, probably due to policies aimed at reducing hospitalization rates.

Cost Control↗
PubMed1995

Migration theories and behavioural models.

"This review presents a probabilistic formulation of the decision making process, leading to a rigorous treatment of migration behaviour for projection purposes....Aggregate-level models may be applied to migration flows for which the objectively measured characteristics of areas of department and destination act as subjectively measured characteristics and stimuli....Individual-level models use event history methods of analysis to introduce a great variety of characteristics of the subject on the decision to move. They lead to projections using microsimulation models. A further step is taken in integrating macro- and microbehavioural models. The use of aggregate and individual characteristics simultaneously leads to more efficient and sophisticated projection models: the factors affecting behaviour at the micro-level cannot be inferred from aggregate studies and conversely."

Behavior↗
PubMed1991

Adjusting for age-related competing mortality in long-term cancer clinical trials.

Mortality related to causes other than the treated disease may have a significant impact on overall survival in long-term clinical trials. We present a model that adjusts for age-related competing mortality when cause of death is missing or only partially available. Through use of a piecewise exponential survival model, we extend relative survival methods to continuous follow-up data, allowing the competing mortality to differ from that of the general population by a scale parameter. An EM algorithm provides a simple way to compute the maximum likelihood estimators (MLEs) and to test hypotheses using widely available software. We compare the bias and relative efficiency of this model to a piecewise exponential Cox model for overall survival. Theoretical results are confirmed by simulations and illustrated with data from a clinical trial in colorectal cancer. This example also shows how age-related and disease-related mortality can be confounded in an analysis of overall survival. We conclude with a discussion of the advantages and disadvantages of the model.

Adolescent↗
PubMed1991

Statistical methods to adjust for date and age misreporting to improve estimates of vital rates in Pakistan.

Misreporting of dates and ages poses serious difficulties for the estimation of the age distribution and birth and death rates in many developing countries. The pervasiveness of these problems is illustrated with data from a well-designed on-going survey in Pakistan, the Pakistan Demographic Survey. Methods for reconciling discrepancies, based on the assumptions of constant misreporting and survivorship patterns, are presented. The reasoning behind these methods could be applied much more generally. Research into the cultural interpretations of age and dates, and the nature of possible biases, is called for.

Birth Rate↗
PubMed1996

Measuring population aging as a function of fertility, mortality, and migration.

Researchers often describe population aging with measures such as proportion of population under 15 years of age, proportion of population 65 years and over, the aged/child ratio (a ratio of the first two measures), median age, and mean age. Investigators of cross-cultural gerontology, too, use such measures to compare population aging between populations. While insights from comparing only the values of an aging measure between two populations may be helpful, results from such comparison can be misleading due to the influences of fertility, mortality, and migration. To show the effects of these demographic processes on measures of population aging, rates of change in five measures of population aging as a function of fertility, mortality, and migration are developed. These rates of change are estimated for various stable populations, for stable populations disequilibrated by fertility and mortality declines and by net migration, and for the population in Japan, 1988-1989. The findings demonstrate that the five aging measures, in general, do not give consistent rate-of-change estimates; they also suggest that directly comparing values of aging measures without considering the levels and patterns of fertility, mortality, and migration will lead to misleading conclusions.

Asia↗
PubMed1987

A survey of Census Bureau population projection methods.

"Population projections methods of the U.S. Census Bureau draw upon several different traditions of forecasting: demographic accounting, judgmental, time series, deterministic, and explanatory. This paper reviews each of the forecasting traditions in population projections, describes the U.S. Census Bureau's current methods for national and state population projections, and proposes new hybrid approaches such as demographic-time series methods for national fertility projections and economic-demographic methods for state migration projections. Throughout the article, possible parallels with forecasting in other disciplines are noted."

Americas↗
PubMed1990

General anaesthesia, a risk factor for complication following induced abortion?

Of the 10,000 abortions performed at the Regional hospital at Modena in Italy between 1982 and 1986, 199 (2%) led to early complications. Investigation of the relationship between the risk of haemorrhage, injury, other complications and all complications and eight explanatory variables revealed that the adjusted odds ratio associated with the use of general anaesthetic compared with local anaesthetic was 4.6 (95% CI, 2.2-9.5) for haemorrhage, 1.3 (95% CI, 0.78-2.2) for injury, 1.6 (95% CI, 1.0-2.6) for other complications and 1.8 (95% CI, 1.4-2.5) for all complications. It is speculated that if the relationship between use of general anaesthetic and risk of complication is causal there could be about 40% fewer cases of complications and 75% fewer cases of haemorrhage following induced abortion if local anaesthesia were used rather than general anaesthesia.

Abortion, Induced↗
PubMed1991

A temporary equilibrium model for international migration.

"This paper is concerned with the existence of temporary equilibria of migration with an overlapping generation structure and analyzes some of its properties. In the first part of the paper sufficient conditions for the existence of a temporary equilibrium of migration (in a given period) are given. In the second part some interesting properties of migration equilibria are analyzed. In particular the effects of differing degrees of information of the individuals on migration equilibria are investigated. Furthermore, it is shown that incomplete information alone suffices to induce migration flows even between countries that can be regarded as 'identical' from an economic point of view."

Behavior↗
PubMed1990

The impact of taxation on the distribution of wealth in an economy with changing population.

The authors examine the determinants of the personal distribution of income and wealth using an overlapping generations model in which all individuals are assumed to be identical except for their inherited wealth. "It is shown that, in general, higher tax rates reduce distributive inequality as long as the rate of interest is exogenously given. In steady state, however, where the rate of interest is determined endogenously, increasing taxation and higher social security payments both diminish the capital labor ratio so that the rate of interest rises. If this interest effect is strong enough then it may outbalance the tendency toward more equality because higher interest rates enhance initial differences in the distribution of both income and wealth and, eventually, the inequality in the distribution of income and wealth in the society." The geographical focus is on developed countries.

Developed Countries↗
PubMed1990

On marriage-specific human capital: its role as a determinant of remarriage.

"This paper focuses on the determinants of the likelihood and timing of remarriage for women: which characteristics of women and their first unions are conducive to quick remarriage and which are associated with low remarriage probabilities?... By analyzing the role of transferable marriage-specific capital as an asset, the present paper suggests a reinterpretation of past results and shows that such human capital constitutes an important component of women's gains from remarriage....[It] studies the determinants of remarriage separately for white and black women. The effects of the duration of first union and the presence of children from that union on remarriage probabilities are found to differ by race, results which can be interpreted within the context of the model developed here." Data from the 1982 U.S. National Survey of Family Growth are used to test the model.

Black or African American↗
PubMed1990

Unemployment and marital dissolution.

"This paper analyses the effects of unemployment on the probability of marital dissolution. Based on panel data for a sample of Danish married couples, we estimate a dynamic model for the probability of marital dissolution where we take into account the possible effects of unemployment for both spouses. We also control for other factors such as education, age, presence of children, place of residence, health and economic factors. The empirical results show that unemployment seems to be an important factor behind marital instability. However, only unemployment of the husband has an effect, and this effect is immediate."

Age Factors↗
PubMed1988

On tests for sex preferences.

"This paper presents a critical evaluation of three widely used tests for sex preferences: sex ratio, parity progression ratio and ordinary least squares [OLS] regression of birth interval. We show that under some appropriate conditions, the sex ratio is a valid test for sex preferences. The methods of parity progression ratio and OLS regression of birth interval fail to deal with right censoring and time varying covariates, which reduce the power of the tests. We suggest the use of hazard estimation to test for sex preferences. We demonstrate the differences among the tests by analyzing the retrospective fertility histories of the Chinese and the Malays in Malaysia. We find that unlike the two conventional methods, the hazard estimation gives clear and strong evidence of sex preferences among the Chinese in Malaysia."

Asia↗