Fertility Decline in Prussia: Estimating Influences on Supply,Demand, and Degree of Control

Change in marital fertility in 407 Prussian Kreise from 1875 to 1910 is modeled to depend on the gap between the number of desired surviving births, N*, divided by child survival, s, and the number that would be born under natural marital fertility, M, given the age at marriage. Some fraction of this gap is averted, depending on the propensity to avert unwanted births, D. Although none of these components is observed directly, we can estimate each indirectly under strong assumptions. Decline in N*/s accounts for twice as much of the decline in fertility as does an increase in D. Natural fertility rose during the period. Unwanted births increased slightly, despite a tripling of births averted. The most important causes of decline in N* were increases in female labor supply, real income, and health workers. A rising level of education is the most important cause of increasing propensity to avert births. Demand-side changes were important causes of the transition, but changes in readiness to contracept also were important, as was the interaction of the two.     

A fertility analysis of New Zealand marriage cohorts

New Zealand annual returns of non-Maori live legitimate births 1913 to 1955 were tabulated longitudinally by marriage duration and birth order. The figures were used as numerators of fertility rates of forty marriage cohorts, specific for duration and birth order ; the twenty-four oldest cohorts had virtually completed fertility. For the denominators of the rates, the cohorts of initial size (estimated by a method similar to that described by P. H. Karmel) were survived by observing changes over time through divorce, death, widowhood, war-widowhood, and net external migration. The aim was to provide a set of data of the best possible approximation on variations of cohort fertility.

Total cohort rates, cumulated for twenty years’ duration of marriage, and segmental rates of relevant sub-periods are given for parities o to 7+. Total rates of the cohorts of completed fertility yielded values of family size, and were also used for parity progression ratios (by L. Henry’s formula). Segmental rates permitted a study of changes in timing maternities.

The analysis, which needs as a corollary a nuptiality analysis, is concerned, so far with past experience. It confirms the decline in number and proportion of large families. Both the parity progression ratios, and segmental rates of cohorts of as yet incomplete fertility, suggest some recent recovery in three- and fourchild families. For total fertility, such recovery might even be more significant than the observed decline in large families. On the other hand, birth-order specific changes in timing suggest lengthening of intervals among older cohorts as a trend upon which is superimposed the fluctuation due to postponement of, and recovery of a portion of postponed maternities. A construction of hypothetical timing patterns for incomplete cohorts by a simplified method of projection does not lead very far without support of observations on spacing that differentiate for family size.     

The demographic transition in the Korean peninsula, 1910-1990: South and North Korea compared

North and South Korea have both experienced demographic transition and fertility and mortality declines. The fertility declines came later in North Korea. In 1990, the population was 43.4 million in South Korea and 21.4 million in North Korea and the age and sex compositions were similar. This evolution of population structure occurred despite differences in political systems and fertility determinants. Differences were in the fertility rate and the rate of natural increase. The total fertility rate was 2.5 children in North Korea and 1.6 in South Korea. The rate of natural increase was 18.5 per 1000 in North Korea and 9.8 in South Korea. Until 1910, the Korean peninsula was in the traditional stage characterized by high fertility and mortality. The early transitional stage came during 1910-45 under the Japanese annexation. Health and medical facilities improved and the crude birth rate rose and then declined. With the exception of the war years, population expanded as a function of births, deaths, and international migration. Poor economic conditions in rural areas acted as a push factor for south-directed migration, migration to Japan, and urban migration. Next came the chaotic stage, during 1945-60. South Korean population expanded during this period of political unrest. Repatriation and refugee migration constituted a large proportion of the population increase. Although the war brought high mortality, new medicine and disease treatment reduced the mortality rate after the war. By 1955-60, the crude death rate was 16.1 per 1000 in South Korea. The crude birth rate remained high at 42 per 1000 between 1950-55. The postwar period was characterized by the baby boom and higher fertility than the pre-war period of 1925-45. Total fertility was 6.3 by 1955-60. The late transitional stage occurred during 1960-85 with reduced fertility and continued mortality decline. By 1980-85, total fertility was 2.3 in the closed population. The restabilization stage occurred during 1985-90, and fertility declined to 1.6. In North Korea, strong population control policies precipitated fertility decline. In South Korea, the determinants were contraception, rising marriage age, and increased use of abortion concomitant with improved socioeconomic conditions.     

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 negligible influence of premarital cohabitation on marital fertility in current danish cohorts, 1975

This paper studies the influence of premarital cohabitation on marital fertility by applying life table methods to data for cohorts of Danish women born in 1926–1955, collected in retrospective interviews made in 1975. For each five-year cohort, the data have been analyzed by duration of marriage or by duration since previous birth, for women who had no reported births before marriage. Our main empirical results are: (a) that women who married at age 15–19 had higher rates of marital first and second births than those married at ages 20–24, and (b) that premarital cohabitation had very little influence on births of these two first orders in our data.     

Declining world fertility: trends,causes, implications

This Bulletin examines the evidence that the world's fertility has declined in recent years, the factors that appear to have accounted for the decline, and the implications for fertility and population growth rates to the end of the century. On the basis of a compilation of estimates available for all nations of the world, the authors derive estimates which indicate that the world's total fertility rate dropped from 4.6 to 4.1 births per woman between 1968 and 1975, thanks largely to an earlier and more rapid and universal decline in the fertility of less developed countries (LDCs) than had been anticipated. Statistical analysis of available data suggests that the socioeconomic progress made by LDCs in this period was not great enough to account for more than a proportion of the fertility decline and that organized family planning programs were a major contributing factor. The authors' projections, which are compared to similar projections from the World Bank, the United Nations, and the U.S. Bureau of the Census, indicate that, by the year 2000, less than 1/5 of the world's population will be in the "red danger" circle of explosive population growth (2.1% or more annually); most LDCs will be in a phase of fertility decline; and many of them -- along with most now developed countries -- will be at or near replacement level of fertility. The authors warn that "our optimistic prediction is premised upon a big IF -- if (organized) family planning (in LDCs) continues. It remains imperative that all of the developed nations of the world continue their contribution to this program undiminished."     

Fertility and economic and social development in Turkey: a cross-sectional and time series study

Abstract The paper explores the impact of modernization on the fertility levels in Turkey, which started deliberate efforts at economic, social, and political transformation in the early 1920s. It is a disaggregative study using 'province' as the unit of observation. A relatively consistent series of data on population and various economic and social variables was available with quinquennial censuses starting with the 1940 Census. The technique of reverse projection is used to estimate provincial crude birth rates. Since 1955 there has been a consistent decline in the fertility level. A chain-relationship model is estimated using both cross-sectional and panel data. A major finding of the study is that in Turkey, continuing modernization and the concomitant spread of female education will result in a continuing decline in the fertility rate. This negative influence, stable and substantial over time, is largely due to factors other than the usual association between education and opportunity cost of female employment, such as changing attitudes and tastes. Also with the spread of economic and social development influencing the society's norm for average age at marriage and the proportion of women married, the marital rate, though not so significant as education, imparts a direct depressing effect on the aggregate period fertility rate at any given time.     

Fertility changes in Latin America in periods of economic uncertainty

We explored the relation between fertility and the business cycle in Latin America. First, we used aggregate data on fertility rates and economic performance for 18 countries. We then studied these same associations in the transitions to first, second, and third births with DHS individual data for ten countries. The results show that in general, childbearing declined during economic downturns. The decline was mainly associated with increasing unemployment rather than slowdowns in the growth of gross domestic product, although there was a positive relationship between first-birth rates and growth. While periods of unemployment may be a good time to have children because opportunity costs are lower, in fact childbearing was reduced or postponed, especially among the most recent cohorts and among urban and more educated women. The finding is consistent with the contention that, during this particular period in Latin America, income effects were dominant.     

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.     

Europe's second demographic transition

By 1985, fertility rates in Europe were below the replacement level of 2.1 births/woman in all but Albania, Ireland, Malta, Poland, and Turkey, following a steady decline from a 1965 postwar peak well above 2.5 in Northern, Western, and Southern Europe and an erratic trend from a lower level in Eastern Europe. Natural decrease (fewer births than deaths) had begun already in Austria, Denmark, Hungary, and the Federal Republic of Germany and can be expected shortly in many other countries. According to current UN medium projections, Europe's population (minus the USSR) will grow only 6% between 1985 and 2025, from 492 to 524 million and 18.4% of the population in 2025 will be 65 and over. The decline to low fertility in the 1930s during Europe's 1st demographic transition was propelled by a concern for family and offspring. Behind the 2nd transition is a dramatic shift in norms toward progressiveness and individualism, which is moving Europeans away from marriage and parenthood. Cohabitation and out-of-wedlock fertility are increasingly acceptable; having a child is more and more a deliberate choice made to achieve greater self-fulfillment. Many Europeans view population decline and aging as threats to national influence and the welfare state. However, governments outside Eastern Europe, except for France, have hesitated to try politically risky and costly economic pronatalist incentives. As used in Eastern Europe, coupled with some restrictions on legal abortion, such incentives have not managed to boost fertility back up to replacement level. Immigration as a solution is unfeasible. All countries of immigration have now imposed strict controls, tried to stimulate return migration of guestworkers recruited during labor shortages of the 1960s and early 1970s, and now aim at rapid integration of minorities. Only measures compatible with the shift to individualism might slow or reverse the fertility decline, but a rebound to replacement level seems unlikely and long-term population decline appears inevitable for most of Europe.     

Contraceptive practice required to meet a prescribed crude birth rate target: a proposed macro-model (tabrap) and hypothetical illustrations

TABRAP (TArget Birth Rate Acceptor Program) is a computer programmed model that provides a direct solution to the problem of determining the total annual numbers of contraceptive acceptors required to achieve a prescribed crude birth rate target path. Applied to an initial population for which age structure, the fertility schedule, and expected trends in life expectancy and age-specific proportions of females married are known, TABRAP incorporates the following factors: age at acceptance, with acceptors drawn from currently married nonusers; age-method-specific attrition rates of users; a potential fertility schedule of acceptors that allows for aging and sterility; and allowance both for postpartum anovulation and nine months for gestation to time properly the averted births. TABRAP generates annual data on acceptors, couple-years of use, births averted and age-specific fertility rates that meet the crude birth rate target. Resulting changes in population size, age structure and crude vital rates, also yielded, are invariant with respect to acceptor age and method mix. Assuming a target to reduce the crude birth rate from 45 to 30 in ten years, TABRAP is illustrated for seven mixes of acceptor age-method combinations applied to a population approximately that of Thailand, circa 1965.     

The Surprising Global Variation in Replacement Fertility

It is frequently assumed by the general public and alsoby some population experts that the value ofreplacement-level fertility is everywhere an averageof 2.1 lifetime births per woman. Nothing could befurther from the truth. The global variation inreplacement fertility is substantial, ranging by almost1.4 live births from less than 2.1 to nearly 3.5. Thisrange is due almost entirely to cross-country differencesin mortality, concentrated in the less developed world.Policy makers need to be sensitive to own-countryreplacement rates. Failure to do so could result infertility levels that are below replacement and lead tolong-run population decline. For example, the currentreplacement total fertility rate for the East Africa regionis 2.94. Lowering fertility to 2.10 would, under currentmortality conditions, result in a regional birthrate 29 percentbelow replacement.     

Post-disaster fertility: Hurricane Katrina and the changing racial composition of New Orleans

Large-scale climate events can have enduring effects on population size and composition. Natural disasters affect population fertility through multiple mechanisms, including displacement, demand for children, and reproductive care access. Fertility effects, in turn, influence the size and composition of new birth cohorts, extending the reach of climate events across generations. We study these processes in New Orleans during the decade spanning Hurricane Katrina. We combine census data, ACS data, and vital statistics data to describe fertility in New Orleans and seven comparison cities. Following Katrina, displacement contributed to a 30% decline in birth cohort size. Black fertility fell, and remained 4% below expected values through 2010. By contrast, white fertility increased by 5%. The largest share of births now occurs to white women. These fertility differences—beyond migration-driven population change—generate additional pressure on the renewal of New Orleans as a city in which the black population is substantially smaller in the disaster’s wake.     

Birth control,income redistribution,and the rate of saving: The case of Mexico

If different groups of people in a low-income society save at different average rates, a program of birth control may affect the aggregate rate of saving by changing the relative shares of income accruing to these groups. A model is outlined in which this process occurs. The only group that saves is profit recipients; peasants and secondary sector employees consume all their income. A decline in fertility leads to a lower demand for food and a lower price of food. This results in a lower money supply price of labor in the secondary sector, and hence greater profits and greater saving. On the other hand, a fertility decline may eventually produce a higher real standard of living among rural workers, hence a higher supply price of secondary sector labor, lower profits and lower saving. These effects are investigated in a simulation of Mexican economic growth with (a) constant high fertility and (b) a declining birth rate such as might occur if a successful national birth control program were instituted. The birth control program results in a higher rate of aggregate saving over the first several decades, and eventually a lower rate of saving once a higher standard of living has been attained.     

Maybe Next Month? Temperature Shocks and Dynamic Adjustments in Birth Rates

We estimate the effects of temperature shocks on birth rates in the United States between 1931 and 2010. We find that days with a mean temperature above 80°F cause a large decline in birth rates 8 to 10 months later. Unlike prior studies, we demonstrate that the initial decline is followed by a partial rebound in births over the next few months, implying that populations mitigate some of the fertility cost by shifting conception month. This shift helps explain the observed peak in late-summer births in the United States. We also present new evidence that hot weather most likely harms fertility via reproductive health as opposed to sexual activity. Historical evidence suggests that air conditioning could be used to substantially offset the fertility costs of high temperatures.     

Fertility and desired fertility: Longitudinal evidence from Thailand

Summary The validity and usefulness of 'desired additional children' and 'ideal family size' as predictors of fertility are analysed in this paper on the basis of longitudinal survey data from Thailand. First, the extent of measurement error in these variables is considered, and it is concluded that the error variance and the true variance are of similar orders of magnitude. Secondly, the changes in attitudes subsequent to births and deaths of children are investigated. It is found that the number of additional children desired is decreased by births and increased by deaths, but less than would be expected if 'desired additional children' represented an unchanging target family size. 'Ideal family size' is almost unaffected by births and deaths. Thirdly, the contribution of attitudinal variables to behavioural models is examined. It is found that desired fertility is explained no better than fertility in a standard economic model. A birth function separating desired children from identifiable physiological factors as explanatory variables indicated that the former was just significant. A model of contraceptive acceptance also found desired fertility to be a significant determinant. Thus, desired fertility can be successfully integrated into behavioural models. But on the whole, its explanatory power was weak, and it was concluded that the independent use of this variable does not significantly improve on models which relate fertility to socio-economic variables directly.     

Parity-specific fertility intentions and uncertainty: the United States, 1970 to 1976

A theoretical and analytic model of fertility intentions is proposed which treats “don’t know” responses and other uncertain responses as distinct from more firm intentions. Methodologically, these analyses show that “don’t know” responses need not be treated as missing data, but instead are both valid and meaningful responses. Furthermore, eliminating these uncertain respondents would have the negative effects of distorting across survey comparisons in intentions due to shifts in aggregate uncertainty, reducing the likelihood of accurately detecting shifts in fertility intentions, and lessening the representatives of the sample analyzed. Substantively, in conjunction with Morgan (1981), these results show that the sharp 1965–76 decline in the likelihood of intending more births at parities 2 through 5 occurred as women halted childbearing at minimal acceptable levels and postponed further childbearing. With time (or age), this delayed fertility became fertility about which the respondent was uncertain and, finally, fertility foregone. Since 1970, similar shifts are observed at parities 0 and 1, perhaps foreshadowing an increase in voluntary childlessness and one-child families.     

A model of numbers of births in three countries,with persistent forty-year cycles

This paper describes a model which relates fertility to partner availability, an aspect of relative cohort size. Partner availability is affected by the tendency for males to reproduce at a later age than females. For women born at a time of rising birth rates, there is a shortage of slightly older men as potential partners. Women born when birthrates are falling enjoy a surplus of older men from which to choose. This model is believed to be the first non-linear demographic feedback model involving feedbacks through marriage squeezes in which empirically estimated values of the parameters imply persistent limit cycles. The deterministic model makes births in each five-year period a function of births in previous five-year periods. The form of the function is chosen to model the effect of partner availability upon entry into reproductive relationships, and therefore on age-specific fertility. Marriage rates are not modeled directly. The model was developed from data for more than a century from England and Wales, New Zealand, and the US. The demographic transition is modeled with a logistic function and age-specific fertility rates are estimated using lognormal distributions. The stepwise inclusion of a partner availability estimate in the model showed that it accounts for 29% of otherwise unexplained variance. Projected future births stabilize in sustained or limit cycles with periods a little longer than 40 years, and amplitudes of at least 7% of the mean. The necessary conditions for cycle persistence are outlined on a graph of maximum and minimum fertility parameters.     

A cohort analysis of the timing of first birth and fertility in Ghana

This paper examines the nature of the inverse association between age at first birth and fertility across successive generations of Ghanaian women. Within the context of enhanced non-marital opportunities for contemporary women and declining fertility, we develop a rationale for and test the hypothesis that in a medium fertility environment as currently found in Ghana, the effect of age at first birth on fertility becomes more important than ever before. Five birth cohorts were identified (1938–1944; 1945–1949;1950–1954; 1955–1959; 1960–1964)from a merged file of the 1988, 1993 and 1998 Ghana Demographic and Health Surveys. The analyses were restricted to women over 35 years old at the time of the surveys, which allowed us to use current parity as a reasonable proxy for completed fertility. Preliminary results suggest that women who had first births early tend to have a higher number of births than those whose first births occur late, regardless of birth cohort. In multivariate analyses, the effect of age at first birth as a determinant of fertility was found to be more substantial among later cohorts. The implications of the findings are discussed.     

Missing the Target? Correspondence of Fertility Intentions and Behavior in the U.S.

Building on a framework suggested by Bongaarts (2001)and using data from the 1979 National LongitudinalSurvey of Youth, we describe the correspondencebetween intended family size and observed fertilityfor the 1957 to 1961 birth cohorts of U.S. women andmen. Over an 18-year period (1982–2000), we showthat while aggregate intentions are quite stable,discrepancies are very common at the individual level.Women and men were more likely to err in predictingnumber of additional births in the period 1982–2000 thanto hit their target number. A very strong predictor of over-and underachieving fertility is initial intended parity. Thosewho intended more than two children tended to have fewerchildren than intended, while those who intended fewer thantwo children tended to have more children than intended. Inaddition and consistent with life course arguments, thoseunmarried in 1982, childless in 1982, and (for women) stillin school in 1982 were most likely to underachieve their 2000intended parity (i.e., have fewer children than intended). Weconclude by reflecting on how the circumstances that allowdiscrepancies between intentions and behavior to almost``balance'' in the U.S. may cumulate differently elsewhere toproduce much lower fertility.