Seasonal variation in basic demographic phenomena (the example of Latvian SSR)

The existence of seasonal variation in demographic phenomena in the USSR is illustrated using data for Latvia. The authors provide evidence of seasonal variations in births, marriages, and infant mortality over the period 1970-1986. Changes in the pattern of seasonal variation over time are also noted.     

Seasonal patterns of fertility measures: theory and data

The distribution of births by month exhibits a seasonal pattern in most populations. The monthly marital fertility rate for an area of Bangladesh provides a good example of the seasonal periodicity. Seasonal patterns of measures of reproduction in a population of married women are considered. Equations are developed that predict the seasonal patterns of these alternative measures under the assumption that the fertility rate (R) follows a trigonometric curve. This is followed by an empirical analysis of the measures in a Bangladesh population that has a pronounced seasonal fertility. The investigation is intended both to validate the theoretical framework developed in the 1st part of the paper as well as to determine whether seasonal variation in actual populations is sufficiently large to affect the alternative measures significantly. 4 measures are considered: pregnancy prevalence (PP)--the proportion of married women who are pregnant at the survey date; mean open birth interval (MOI)--the time from the last live birth to the date of the survey for parous women and from the time of marriage to the date of the survey for nulliparous women; mean closed interval-birth (MCIB)--the mean interval between the last 2 live births for married women who have a birth in the period immediately preceding the survey date; and mean closed interval-woman (MCIW)--the mean interval between the last 2 live births for women who have had at least 2 children by the time of the survey. It is assumed that the seasonal pattern of the fertility rate of a population follows a cosine curve and that there is no trend in annual fertility from year to year. The lag and relative variability of the other measures are considered in comparison with the fertility rate curve. The predictions from this theoretical effort, when compared with observed patterns and trigonometric regression results for each measure in data from Bangladesh, are shown to be quite accurate. The figure and regression results show that R, PP, and MOI have definite seasonal periodicity, but MCIB and MCIW do not display any seasonal patterns. If there is a secular trend in fertility in addition to seasonality, these relationships between the seasonal patterns of the measures may no longer hold. There is a disadvantage to using closed interval measures, for they are unable to detect effects of limiting of childbearing in a population since they are based only on information from women who have births.     

The analysis of seasonality in births and deaths

"Monthly data on live births and stillbirths and quarterly data on mortality and infant mortality in Poland are analyzed for the period 1983-1985. The aim is to evaluate and compare seasonal fluctuations in these variables in Katowice voivodship and in Poland as a whole. Effects of seasonal factors are estimated separately for males and females and urban-rural areas via a regression model. For births, effects of seasonality are similar in Katowice and Poland, while for deaths significant differences are observed.     

Seasonal daily effect on the number of births in Israel

Previous studies have observed a 7-day cycle with the least number of births occurring on Sundays. This study was aimed at characterizing the daily effect on the number of births in Israel, where Sunday is a regular working day and Saturday is a nonworking day. It was hypothesized that fewer births would be noted on Saturday rather than Sunday and fewer births on Jewish holidays. The data consisted of a random sample of live births during 1975. A robust time series procedure was used for the data analysis. As expected, the number of births was much smaller on Saturdays than on other weekdays (10% reduction). The seasonal component for Sundays was greater than that for any other day due to births delayed from Saturday and scheduled induced births. The number of births was not reduced as much on Saturdays during spring and summer as during fall and winter. In addition, fewer births occurred on most Jewish holidays. However, an unexpected and extremely high number of births was noted on Yom Kippur and the day after. It is speculated that the strain and fasting during this holiday promoted labor induction. In 21 of the 52 weeks in the study period, the least number of births occurred on a Saturday, and the number of births was less than the mean of the remaining 6 days in 46 of these weeks. Similarly, in 17 of the 52 weeks, the greatest number of births occurred on a Sunday, and the Sunday births exceeded the mean of Monday-Friday births in 35 of these weeks. Thus, these results confirm the study hypothesis and are believed to reflect intervention in childbirth.     

中国月度数据的季节调整：一个新方案

 本文针对中国特定的节假日效应和交易日效应对季节调整问题提出了新的方案,包括移动节假日效应（如春节、中秋节、清明节、端午节等）、黄金周效应、五天工作制效应等;论文利用新的调整方案对我国社会消费品零售总额的月度数据进行了季节调整,诊断结果表明,新方案能比较充分地提取各种季节特征;论文对我国季节调整问题提出了针对性建议。     

A Method for Seasonally Adjusting Time Series With Variation in the Seasonal Amplitude

The official seasonally adjusted figures of the unemployment series in the Netherlands proved to be unsatisfactory in the years 1976 until 1980 because of the occurrence of a residual seasonal pattern in the adjusted series. There is indication that this failure is due to the presence of variations in the seasonal amplitude of the unemployment series. To improve this unsatisfactory state of affairs further research on methods of seasonal adjustment was undertaken at the Netherlands Central Bureau of Statistics. The outcome, method CPBX11, combines features of two methods that have been used officially, CENSUS X-11 and CPB-1. Since December 1980 the Netherlands Central Bureau of Statistics has used CPBX11 to compute seasonally adjusted labor market series. In this article we review in short the literature on seasonal adjustment and compare the performance of the three procedures referred to above in adjusting the series Unemployment in Construction and Live Births (per 1,000 of the mean population) for the Netherlands. The CPBX11 method yields more satisfactory results, especially for the first series.     

Statistical materials

Official population data for the USSR are presented for 1985 and 1986. Part 1 (pp. 65-72) contains data on capitals of union republics and cities with over one million inhabitants, including population estimates for 1986 and vital statistics for 1985. Part 2 (p. 72) presents population estimates by sex and union republic, 1986. Part 3 (pp. 73-6) presents data on population growth, including birth, death, and natural increase rates, 1984-1985; seasonal distribution of births and deaths; birth order; age-specific birth rates in urban and rural areas and by union republic; marriages; age at marriage; and divorces.     

A note on a transient queuing system of a linear birth–immigration process in presence of twin births

In this article, we consider a simple transient queuing system, i.e., a linear birth process with immigration in the presence of twin births. We find the differential-difference equation and also the probability-generating function (p.g.f.) for this process. Again, we generalize it into a linear birth process with immigration in the presence of both single birth or twin births and again for the case of multiple births. From the p.g.f. of linear birth process with immigration in the presence of twin births, we find some particular transient queuing processes like linear birth process with twin births and simple immigration process. Direct derivations of mean and variance of these processes are also discussed without using the generating functions.     

The Modeling and Seasonal Adjustment of Weekly Observations

Several important economic time series are recorded on a particular day every week. Seasonal adjustment of such series is difficult because the number of weeks varies between 52 and 53 and the position of the recording day changes from year to year. In addition certain festivals, most notably Easter, take place at different times according to the year. This article presents a solution to problems of this kind by setting up a structural time series model that allows the seasonal pattern to evolve over time and enables trend extraction and seasonal adjustment to be carried out by means of state-space filtering and smoothing algorithms. The method is illustrated with a Bank of England series on the money supply.     

A new look at an old problem: Finding temporal patterns in homicide series—the Canadian case

It is believed by criminologists that the incidence of crimes committed against persons is highest in the summer. Knowledge about the annual patterns and other temporal behavior of such crimes can help authorities in prevention. The objective of this study is to reveal the temporal behavior of murders in Canada and assess if they are affected by trend-cyclical and/or seasonal influences. The series analyzed comprise the period 1961 to 1980 and are classified according to suspects and victims. Only the quarterly series display a significant seasonal pattern, with the peak occurring in the third quarter. We have also analyzed the relationship between the trend cycle of the murder series and two other variables, namely unemployment rate and rate of growth of the 15-to-44 age group.     

THE BEHAVIOR OF HEGY TESTS FOR QUARTERLY TIME SERIES WITH SEASONAL MEAN SHIFTS

ABSTRACT

This paper studies the behavior of the HEGY statistics for quarterly data, for seasonal autoregressive unit roots, when the analyzed time series is deterministic seasonal stationary but exhibits a change in the seasonal pattern. We analyze also the HEGY test for the nonseasonal unit root. the data generation process being trend stationary too. Our results show that when the break magnitudes are finite, the HEGY test statistics are not asymptotically biased toward the nonrejection of the seasonal and nonseasonal unit root hypotheses. However, the finite sample power properties may be substantially affected, the behavior of the tests depending on the type of the break.     

Age patterns of marital fertility: revising the Coale-Trussell method

"This article revises the Coale-Trussell method for analyzing data from the World Fertility Survey by proposing and testing alternative log-linear and log-multiplicative models. The models, in one form or another, represent the structural constraint underlying the Coale-Trussell method on the variation in the age pattern of human fertility. With a Poisson distribution assumption for the number of births, several parameters of the models are simultaneously estimated via maximum likelihood. It is shown that the new approach can be adopted whenever fertility limitation is compared across multiple populations or subpopulations."     

基于季节调整的CPI统计环比指数研究

本文首先阐述了季节调整与统计环比指数的必要性,简要介绍了X-12-ARIMA与TRAMO/SEATS季节调整原理,然后运用X-12-ARIMA程序对中国1997年1月至2010年5月CPI月度数据进行季节调整,再运用TRAMO/SEATS方法解决季节调整程序中中国春节因素问题。接着由季节调整后的数据计算得到月环比CPI,对月环比CPI和同比增加率进行了比较,结果显示月环比CPI领先同比CPI。最后利用TRAMO/SEATS程序建立ARIMA模型（210）（011）进行了24个月的预测,预测结果显示,未来24个月内我国消费者物价指数温和上升,不会发生大的通货膨胀,但是存在一定的通胀压力。     

The sex ratio at birth

Several aspects of the disparity in birth ratio of males over females are discussed including variations among different races, variations by order of birth, by age of the parent, and in multiple births. Avenues of statistical exploration are suggested in an attempt to indicate certain peculiarities in nature. The Negro population in the United States has a sex ratio of 102 males to 100 females as opposed to 105:100 for whites, a highly significant difference. Inferences from these statistics are suggested for study of the sex ratios of mixed unions. The group classified as Mulatto show a lower sex ratio and further analysis of this was suggested including examination of slave records. For the white population sex ratio declines from 106.2 to 102.9 between 1st order and 7th order births. This is highly significant. However, nonwhite determinations were more irregular. Data limitations on sex ratio by age of parent prevented conclusive results. Multiple births among whites show a decline from 105.3 for single live births to 103.2 for twins and 86.1 for all other plural deliveries. Among nonwhites these ratios are 102.3, 99.7, and 102.6 respectively. Further information should be developed using the multiple facts relating to the sex ratio at birth.     

中国城市生猪规模养殖模式的生产率变动分析

运用基于两阶段DEA的Malmquist生产率指数模型,分析2001—2008年中国城市生猪规模养殖模式的全要素生产率指数,得出结论：全国城市TFP增长率总体上呈＂V＂状,平均增长率为负;技术进步效率退化是造成生产率负增长的主要因素;产业风险是造成生产率剧烈波动的根本原因。提出建议：因地制宜,合理布局;品种引进,品种选育;技术培训,科学饲养;生猪保险,生猪期货。     

The impact of education on third births. A multilevel discrete-time hazard analysis

We propose to use multilevel discrete-time hazard models to assess the impact of societal and individual level covariates on the timing and occurrence of third births. We focus mainly on the impact of educational attainment on third births across 15 European countries. From the analysis in this paper, the effect of education on the propensity to have a third child is found to be negative. This education effect is not significantly weakened by the Nordic countries, but living in Scandinavia does increase the hazard for a third birth.     

中国对外贸易质量剖析

如何科学地评价中国对外贸易质量的状况,是制定有效政策以推进我国对外贸易发展方式转型的前提条件之一.本文利用经济理论判断和统计分析相结合的方法,从世界银行WDI数据库中,选取并构造了1980-2010年反映中国对外贸易状况的6个因变量和9个自变量.通过实证分析,在静态和动态两个维度,描述了改革开放30多年来中国对外贸易质量总体状况的结构变化特征,并提出了相关的政策建议和进一步的研究方向.     

L'analyse de la variation saisonniére quand l'amplitude et la taille sont faibles

Studies of seasonal variation are valuable in biomedical research because they can help to discover the etiology of diseases that are not well understood. Generally in these studies the data have certain characteristics that require specialized tests and methods for the statistical analysis. But the effectiveness of these specialized tests is variable, especially according to the seasonal variation, the dimension of the amplitude in the seasonal variation, and the sample size. The purpose of this paper is to present a test and methods appropriate for the analysis and modeling of data whose seasonal variation has small amplitude and whose sample size is small. This test can detect different kinds of seasonal variation. The results from a simulation study show that the test performs very well. The application of these methods is illustrated by two examples.     

Spatio-temporal modeling of infectious disease dynamics

A stochastic model, which is well suited to capture space–time dependence of an infectious disease, was employed in this study to describe the underlying spatial and temporal pattern of measles in Barisal Division, Bangladesh. The model has two components: an endemic component and an epidemic component; weights are used in the epidemic component for better accounting of the disease spread into different geographical regions. We illustrate our findings using a data set of monthly measles counts in the six districts of Barisal, from January 2000 to August 2009, collected from the Expanded Program on Immunization, Bangladesh. The negative binomial model with both the seasonal and autoregressive components was found to be suitable for capturing space–time dependence of measles in Barisal. Analyses were done using general optimization routines, which provided the maximum likelihood estimates with the corresponding standard errors.     

季度税收与季度GDP的协调关系

税收增长连年超GDP增长,引起人们对税收与经济增长关系是否协调的疑虑。本文对1994年分税制改革以来的季度税收资料,进行季节调整和HP滤波,然后从总体趋势上就税收与GDP的协调关系进行了讨论,包括季度税负、税收弹性、季节指数等。基本结论是：总体趋势上税收与经济指标之间是协调的,但增长率关系上存在着税收超经济增长的现实,季度之间也存在着一定程度的不平衡。