A fertility survey in the Maltese Islands

In order to determine whether fertility is declining in Malta, a sample was taken by the Maltese Central Statistical Office in mid-1955, along the line of the Family Census of 1946 in Great Britain. The size of the sample was 10,000, and the response very good. The sample shows no noticeable decline in fertility since the marriage cohorts of the beginning of the century. Some decline is noticeable int he fertility of the later durations of marriage, but completed family size remained more than 6 for the cohorts of the 1920's. This contrasts with the declining fertility shown by the enquiry in Great Britain, and the figure of 6 is in fact much greater than the completed families born to cohorts in Great Britain at the end of Queen Victoria's reign. Fertility seems in fact to be still rising in Malta for the first 18 months of marriage; and the first decade of marriage continues to show an average of 4 births. It seems therefore that the recent decline in the birth rate is to be attributed to changes in the populatino structure rather than in marital fertility. The continued high fertility implies a very rapid rise in population in the absence of emigration.     

Systematic and chance components in fertility measurement

Abstract A Monte Carlo simulation model of fertility is developed to incorporate a decline in fecundability with age of women as well as a variation between women, and a family planning strategy in which couples prefer certain sizes of families and seek to lengthen the last planned birth interval. In the simulation of family planning and non-family planning populations, segmental parity tables are computed. These are tables in which the numbers of women in the columns representing the completed family sizes are sub-divided by rows representing the sizes of the families for shorter durations of marriage. The couples' success in their plans, under various conditions, and the rapidity with which family sizes stabilize, are among the results obtained from the simulation. The application of the tables to the estimation of family size preferences from observed family size distributions is also discussed.     

Age at last birth and its components

This paper examines the ways in which the behavior of twentieth century cohorts of American women changed simultaneously in the three components of fertility that determine age at last birth--age at first birth, spacing between subsequent births, and parity progression ratios of subsequent births--to produce changes in the timing of the completion of childbearing. It decomposes changes in the mean age at last birth among cohorts and between whites and nonwhites to changes in these three components. To perform these analyses, we developed and applied a method to estimate the distributions and means of ages and last births, birth intervals, and parity progression ratios from age- and parity-specific fertility rates available from vital statistics data. Results show that the cohorts increased and decreased their age at first birth, birth intervals, and parity progression ratios of lower and higher birth orders in almost every possible combination so as to achieve a relatively young age at final birth.     

Birth spacing and fertility limitation: a behavioral analysis of a nineteenth century frontier population

Our analysis of changing birth interval distributions over the course of a fertility transition from natural to controlled fertility has examined three closely related propositions. First, within both natural fertility populations (identified at the aggregate level) and cohorts following the onset of fertility limitation, we hypothesized that substantial groups of women with long birth intervals across the individually specified childbearing careers could be identified. That is, even during periods when fertility behavior at the aggregate level is consistent with a natural fertility regime, birth intervals at all parities are inversely related to completed family size. Our tabular analysis enables us to conclude that birth spacing patterns are parity dependent; there is stability in CEB-parity specific mean and birth interval variance over the entire transition. Our evidence does not suggest that the early group of women limiting and spacing births was marked by infecundity. Secondly, the transition appears to be associated with an increasingly larger proportion of women shifting to the same spacing schedules associated with smaller families in earlier cohorts. Thirdly, variations in birth spacing by age of marriage indicate that changes in birth intervals over time are at least indirectly associated with age of marriage, indicating an additional compositional effect. The evidence we have presented on spacing behavior does not negate the argument that parity-dependent stopping behavior was a powerful factor in the fertility transition. Our data also provide evidence of attempts to truncate childbearing. Specifically, the smaller the completed family size, the longer the ultimate birth interval; and ultimate birth intervals increase across cohorts controlling CEB and parity. But spacing appears to represent an additional strategy of fertility limitation. Thus, it may be necessary to distinguish spacing and stopping behavior if one wishes to clarify behavioral patterns within a population (Edlefsen, 1981; Friedlander et al., 1980; Rodriguez and Hobcraft, 1980). Because fertility transition theories imply increased attempts to limit family sizes, it is important to examine differential behavior within subgroups achieving different family sizes. It is this level of analysis which we have attempted to achieve in utilizing parity-specific birth intervals controlled by children ever born.(ABSTRACT TRUNCATED AT 400 WORDS)     

Fertility decline in Taiwan: A study using parity progression ratios

Taiwan's decline in fertility is studied by using period parity progression ratios. Levels of marriage and motherhood are found to have been high and essentially constant though the late 1980s, suggesting that the decline has been due almost entirely to declines in second and higher order-births. Families with three or more children play an important role in maintaining the current level of fertility. The level of fertility would be even lower without these families. They contributed more than one-half child per woman to the total fertility rate during most of the 1980s. Total fertility rates computed from the period parity progression ratios indicate a substantially higher level of fertility than the conventional total fertility rate; they remained above or at replacement level through 1988. A formal demographic analysis suggests that the conventional total fertility rate has been depressed by shifts in age at childbearing.     

On the tempo of childbearing in England and Wales

Abstract The paper describes a computerized model developed to simulate the fertility of a hypothetical marriage cohort in a closed population. The model was applied to England and Wales fertility data of marriage cohorts of the years 1951 to 1970. For each of these cohorts, the computer was programmed to construct five series of tables showing birth-order probabilities, family size frequency distribution, mean length of intervals between marriage and successive births, parity progression ratios and mean family sizes of fertile women. The results showed that the fertility of the cohorts of women who married between the middle 1950s and the early 1960s was character ized by a declining trend in the frequency of childlessness and by a dramatic increase in the proportion of marriages with two or more children. Since 1964 or so, there has been a downward trend in duration-specific birth-order probabilities. The analysis suggests that the recent drop in fertility may well prove to be the effect of an upward shift in the timing of births as well as a fall in completed fertility.     

Measuring marital fertility control with CPA

Cohort Parity Analysis (CPA) is an indirect method for measuring the extent and timing of the adoption of fertility control within marriage. Cohort Parity Analysis uses 2 sets of parity distributions, 1 from the population under study (the "target" population) and 1 from a similar population in which fertility control is absent (the "model" population). Fertility control is defined as any set of behaviors in the target population that cause its parity progression rates to differ from those of a similar but noncontrolling population. The target population contains an unidentified mixture of controlling and noncontrolling couples for a given age range and marriage duration. The model population is similar in all respects except that it contains no controllers. Examples are taken from urban and rural Irish populations in the 1911 census data. Cohort parity analysis rests on 2 basic assumptions: 1) For every specified marriage duration and marriage age, there exists some parity above which controllers are never found; and 2) Parity progression rates of those in the mixed population who have never initiated fertility control are identical to those in the model population. Further, one must identify a cutoff parity beyond which controllers are presumed not to be found. In these urban Irish examples cutoff parity for each marriage age and duration is set at 20% of that of the noncontrolling rural Irish population. The upper and lower bounds on the percentage of controllers are derived by obtaining the lower and upper bounds on the size of the group at that parity who never controlled and subtracting these estimates from the observed percentage of the target population observed at that parity. Flow charts are used to present the methodology of cohort parity analysis in a simple format. the method is illustrated in the case of Ireland in 1911. Aggregate parity distributions for the county boroughs of Dublin, Belfast, Cork, LOndonderry, Limerick, and Waterford are taken as the target distribution; and parity distributions for those living outside the county boroughs are taken as the model distributions. The analysis shows that 28% of urban-dwelling Irish women who married before age 30 and were married between 4 and 29 years in 1911 used some effective means of fertility control. The parity distributions also show that women who married later controlled their fertility to a greater extent and that between 20.9 and 25.5% of women married 4 years in 1911 had already practiced fertility control by 1911, but only 15.5% of those married 15-19 years had used fertility control by 1911. Cohort Parity Analysis is thus a useful method of examining historical populations in the process of fertility transition.     

Age at marriage and timing of the first birth

Summary An attempt has been made to measure the effect of age at marriage of brides on the timing of the first birth. In Australian vital statistics, first nuptial confinements have been tabulated by age of mothers and by single years of marriage duration in single months for the first two years and by single years for all other durations since 1916. A simple technique has been used to link such data with marriage cohorts. The study briefly reviews the prevailing patterns of the timing of first births by mothers' age at marriage and changes in this pattern since the marriages of the 1925/9 period. The analysis shows that after a period of relative stability of family formation patterns in the 1950s and early 1960s, women married in the late 1960s started postponing the first birth beyond the first two years of marriage. It is suggested that a fraction of the decline in total births recorded in Australia since 1972 can be attributed to the postponement of first nuptial confinements by women married in the late 1960s and early 1970s.     

Multidimensional Life Table Estimation of the Total Fertility Rate and Its Components

Using discrete-time survival models of parity progression and illustrative data from the Philippines, this article develops a multivariate multidimensional life table of nuptiality and fertility, the dimensions of which are age, parity, and duration in parity. The measures calculated from this life table include total fertility rate (TRF), total marital fertility rate (TMFR), parity progression ratios (PPR), age-specific fertility rates, mean and median ages at first marriage, mean and median closed birth intervals, and mean and median ages at childbearing by child’s birth order and for all birth orders combined. These measures are referred to collectively as “TFR and its components.” Because the multidimensional life table is multivariate, all measures derived from it are also multivariate in the sense that they can be tabulated by categories or selected values of one socioeconomic variable while controlling for other socioeconomic variables. The methodology is applied to birth history data, in the form of actual birth histories from a fertility survey or reconstructed birth histories derived from a census or household survey. The methodology yields period estimates as well as cohort estimates of the aforementioned measures.     

Timing effects on first marriage: twentieth-century experience in England and Wales and the USA

Recent substantial declines in first marriage in Western countries have been accompanied by increases in the average age at first marriage. Since the period proportion ever marrying, PEM, is sensitive to cohort tempo changes, the recent fall in the PEM may simply reflect cohort delays in marriage. The importance of timing factors is examined in the light of twentieth-century experience of first marriage in England and Wales and the USA. Using a variant of the Timing Index developed in research on fertility, we measure cohort timing effects for marriage and calculate an adjusted PEM. After examining twentieth-century trends in nuptiality for men and women, we find substantial tempo effects on the period PEM. Adjusted PEM values show a real decline in marriage for cohorts, but that decline is considerably smaller than the one shown by the unadjusted figures. This is especially true for England and Wales, where the decline in marriage was much greater.     

A model of the age patterns of births by parity in natural fertility populations

This research develops a convolution model to express the age patterns of fertility at each birth order in natural fertility populations in terms of six parameters, directly representing the proximate determinants of fertility, and a series of parity level indicators. The parity level indicators at each birth order are simply the proportions of women in a cohort who will eventually have births at each birth order it the age‐related fecundity decline is controlled. The Coale‐McNeil nuptiality model is adopted to represent the age pattern of first marriage rates and the natural fertility schedule employed in the Coale‐Trussell fertility model is incorporated to adjust age effects. The fast Fourier transform is used in solving the model numerically. It proves that the model is able to provide excellent fits to fertility for rural Chinese women in the 1950s.     

The influence of the farm size on the parity of a farming family in Poland

This paper aims at statistical identification of the relationship between the parity of farming families and the area of the farm and the role this variable plays among variables describing the model of families' parity. To reach this objective results of a questionnaire survey were used, one performed among the group of individual farmers' families keeping agricultural accounting in 1985. The analysis covered 1291 rural farming couples who married in the years 1920-1984. According to the results obtained, the thesis posed by W. Stys with regard to positive relationships between parity in a family and the farm's area only relates to marriages entered into between 1920-1964. In single five-year marriage cohorts, a change of shape of this relationship was observed. It took the shape of a parabolic function or polynomial of the third order. The research results showed that in marriage cohorts with finished fertility, variable area of the farm turned out to be almost insignificant in explaining changes in the number of live born children compared to other demographic factors, especially cultural and demographic ones.     

Marital and fertility careers of Russian women born between 1910 and 1934

Women born in Russia in the early decades of this century grew up in a period characterized by profound societal changes. Their lives were affected by often devastating events, in particular World War II, that ravaged society when they were entering their childbearing years. This note presents a detailed demographic analysis of the marital and fertility careers of women born between 1910 and 1934 based on individual retrospective life histories, collected in the most recent (5 percent) 1994 microcensus of the Russian Federation. It assesses the influence of external events on age at first marriage, widowhood, divorce, childlessness, parity, and age at birth. A comparison with younger cohorts shows that the societal disturbances had strong temporary effects. However, the final outcomes were not influenced very much: completed fertility continued its slow, secular decline.     

The Baby Boom and Its Causes: What We Know and What We Need to Know

This study analyzes the timing, magnitude, and volume of the mid‐twentieth century baby boom in European and non‐European Western countries. The baby boom is found to have been especially strong in the non‐European countries, fairly strong in some European countries, and quite weak in others. While the boom has often been linked with postwar economic growth and the recuperation of births postponed during the Depression era, we argue that this is only a limited part of the story. In most cases the recovery of the birth rate started well before the end of World War II, a fact not accounted for by existing theories. We investigate the roles played by the recovery of period as well as cohort fertility, the underlying marriage boom, and the recovery of marital fertility. We identify major puzzles for future research, including the reasons for strongly declining ages at marriage and the role played by contraceptive failure in the rise of high‐parity births.     

Birth delays skew developing world's fertility figures

This article explains that birth delays skew developing world's fertility figures. When successive groups of women who have delayed childbearing start having children, the rapid fertility decline stalls. Such change in the timing of childbearing skews the total fertility rate (TFR). Analysis of the tempo component of TFR trends in Taiwan suggests that tempo effects reduced its TFR by about 10% in the late 1970s and early 1990s and by about 19% in the late 1980s. In Colombia, on the basis of increasing mean maternal age at childbirth between the 1970s and the late 1980s, tempo distortions of the TFR during the most of the 1980s seem likely. Moreover, many developing countries are now experiencing rapid fertility declines that are in part attributable to tempo changes. These changes have accelerated past fertility transitions, but they also make these countries vulnerable to future stalls in fertility when the delays in childbearing end. Since fertility reductions caused by tempo effects lead to real declines in birth rates and hence in population growth, countries that wish to reduce birth rates can take actions that encourage women to delay marriage and the onset of childbearing.     

Cohort disaggregation analysis of fertility data from a sample survey

Social differentials in cumulative fertility revealed by field surveys in a number of countries typically have been interpreted with the implicit assumption that the timing of childbearing within the reproductive period remains constant. However, the reproductive histories that have been collected in such surveys provide a largely unexploited source of data for the analysis of trends in timing. An analysis by birth cohort of the fertility experience of 592 ever-married women surveyed in San Juan, Puerto Rico, in 1966 shows that significant changes in timing have occurred. Women in the more recent birth cohorts are distinguished by earlier childbearing and sustained higher fertility in consecutive age periods. The inter-cohort differences remain when adjustments are made for duration of time in legal and consensual unions.     

A specification of marital fertility by parents’ age,age atmarriage and marital duration

The positive association between wife's age at marriage and fertility experienced at the older reproductive ages, cited in recent natural fertility literature, is explored using Mormon birth cohorts from 1840 to 1879. When this relationship is specified by husband's age at marriage and marriage duration, the results indicate that older-aged husbands depress marital fertility only at higher marriage durations. The general decomposition of age-specific fertility utilizing both mother's and father's age is also considered. The results show that mother's aging is the most important factor, while father's aging has a moderately negative effect under a natural fertility regime.     

Period Parity Progression Ratios and Birth Intervals in England and Wales, 1941–1971: A Synthetic Life Table Analysis

A method is presented for analysing maternity history data to provide period estimates of parity progression ratios, birth intervals and related indices. This is applied to a sample of the marriage and maternity histories from the Census of England and Wales of 1971 and shows: (a) a general increase through the 1950s and into the 1960s in period estimates of marriage and parity progression ratios, especially in the progression from first to second birth; (b) a general acceleration of fertility with, again, the second birth interval becoming particularly short and compact; and (c) very steep declines in third and fourth birth progression ratios from the mid-1960s. Birth interval distributions altered during the period examined. Decomposition of a progression-based total fertility index shows change in the ratios for lower birth orders to have dominated the fertility upswing and declines in ratios for higher birth orders to have initiated the subsequent decline.     

Conceptive delay,nonsusceptible period,and cohort fertility patterns

Demography - A model of cohort fertility pattern by duration of marriage is built on the parameters of conceptive risk, its decline along parity, and the length of the nonsusceptible period. The...     

National Estimates of Cohabitation

Data from the 1987-1988 National Survey of Families and Households are used to provide national estimates of cohabitation trends and levels. The rapid increase since around 1970 is documented over both birth cohorts and marriage cohorts. Almost half of the persons in their early 30s and half of the recently married have cohabited. Changes in the proportion ever married are compared with changes in the proportion who have either married or cohabited. Much of the decline in marriage has been offset by increased living together without being married. The stability of unions of various types is compared. Cohabitations end very quickly in either marriage or disruption. About 60 percent of all first cohabitations result in marriage. Cohabiting unions and marriages preceded by cohabitation are much more likely to break up than are unions initiated by marriage. Multivariate analysis reveals higher rates of cohabitation among women, whites, persons who did not complete high school, and those from families who received welfare or who lived in a single-parent family while growing up.