Rapid Population Change in China, 1952-1982 (1984) / Chapter Skim
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2 Sources and Quality of Data
2 Sources and Quality of Data
Pages 12-38
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From page 12... ...
This survey obtained information about the complete childbearing and marriage histories of a sample of women aged 15-67. The households included in the survey had a population totalling more than 1 million.
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From page 13... ...
Within the past two years, however, the most essential demographic information -- the nu~nJoer of persons of each sex classified by single years of age -- from these two censuses has been published. The Ministry of Statistics has also recently published the Statistical Yearbook for 1983 with hundreds of tables, including annual birth and death rates since 1950.
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From page 14... ...
The second reason for rejecting the hypothesis is that the annual numbers of births derived from a combination of census-based estimates of numbers of women each year and survey-based retrospective data on fertility rates are quite different from official records of the annual number of births. In other words, the fertility histories are in wide disagreement with official data on births and so cannot have been derived from the registers.
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From page 15... ...
During this period, more than 5.7 million household registration personnel, statistical personnel, and other basic-level cadres were mobilized to update household registration throughout the country. They conducted a systematic investigation through household interviews and found and corrected errors: 6.1 double registrations per thousand and 5.4 omissions per thousand.
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From page 16... ...
They conducted the postenumeration survey in the selected sample units household by household and then compared the figures obtained with the figures of the original census enumeration. When errors were found, a second check was made before the data were corrected.
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From page 17... ...
The total population in the survey was a little more than 1 million, involving a sampling fraction of about 1/1,000. The choice of such a very large sample size was based on the calculated number of respondents required to yield 95 percent confidence limits for the peak single-year agespecific fertility rates that would differ by only 5 percent from the rate calculated from the sample, after allowance for the greater variance in a cluster sample than in a simple random sample.1 Because the sample was so large, estimates of age-specific fertility rates and rates of first marriage by single years of age extending back into the 1950s have remarkably low sampling variability.
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From page 18... ...
Figure 4 shows the proportion of women surviving from one census to the next classified by single years of age at the earlier census: the survival ratios are for 1953 to 1964 and 1964 to 1982. Also shown in Figure 4 are survival ratios extracted from a life table expressing the proportion that would survive from birth to each age in a hypothetical cohort subject to the average mortality rate at each age for the intercensal interval.2 The surprising feature of the single-year survival ratios calculated directly from the censuses is that there is so little irregularity.
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From page 19... ...
19 1.1 1 .0 0.9 Z 0.8 0.7 ~ 0.6 0 0.5 ~ 0.4 o O 03 CC cat 0.2 0.1 o 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 o 0 10 20 30 Censuses of 1953 and 1964 - at, \ 40 50 60 70 80 85 AGE Censuses of 1964 and 1982 1 _ 1 1 1 1 1 ~1 , 40 50 60 70 80 85 0 1 0 20 30 AGE FIGURE 4 Proportion of Females Surviving Between Successive Censuses for Each Age (solid line is proportion derived from intercensal life table, dotted line is ratio taken directly from the census enumerations) : China
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From page 20... ...
The data collected and tabulated from the large-scale fertility survey conducted by the Ministry of Family Planning in 1982 are even more remarkable than the census data in their internal consistency. The published tables include rates of childbearing by single years of age and single calendar years for women aged 15-49 for the years from l9SO to 1981.
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From page 21... ...
In short, there are two sets of numbers for the population classified by single years of age from 0 to 11 in 1964 and from 0 to 29 in 1982. One set is taken from the census and the other from estimated births and survival rates from the survey -- the births calculated from retrospective fertility rates combined with interpolated numbers of women and the survival rates from intercensal life tables.
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From page 22... ...
In less and 1982 an adjusted age distribution was constructed by allocating the known or estimated number of persons in the armed services age by age, using a rough estimate of the ratio of males to females at each age based on the ratio at ages prior to the range of military service and the ratio at ages above
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From page 23... ...
by Single Years of Age (dotted line represents original data, solid line includes estimates of males in armed services) , 1953, 1964, and 1982: China
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From page 24... ...
(The adjusted age distributions are given in Table A-2.) A remarkable feature of the male/female ratios in the three censuses is the increase in the ratio with age in all three censuses, from a moderate ratio for the cohorts born around l95l to a ratio of 115 males or more per loo females for those born in 1940, and the continued high ratio of males to females for cohorts born still earlier.
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From page 25... ...
, it may be conjectured that less care was taken in establishing the de jure population of the households than in collecting the detailed marriage and fertility histories. The second anomaly is puzzling information in a table that lists the number of male and female births in 1981 by sex and birth order in the rural and urban populations.
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From page 26... ...
It is scarcely possible that the uniformly higher male/female of urban births and the regular increase in the ratio with birth order in both rural and urban births are the results of sampling quirks The relatively high male/female ratios in higher-order births might be the result of simple underreporting of higher-order females births in the survey. It is understandable that a higher-order birth that occurred contrary to the one-child campaign would be unregistered because the parents would want to conceal such a birth.
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From page 27... ...
The ratio of the official figures to the constructed figures is a valid estimate of the completeness of the official figures since the estimated figures are very consistent with the numbers counted at each age in the censuses. Completeness of official reporting in each year is shown in Figure 8, together with a three-year moving average of completeness.
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From page 28... ...
28 TABLE 1 Annual Number of Births (in millions) from Official Figures and as Calculated from Fertility Rates in Survey and Interpolated Populations, and Estimated Completeness of Reporting, 1953-82: China Number of Births .
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From page 29... ...
The difference between the total number of births between two censuses and the intercensal growth in population is the total number of deaths in that interval. The figure used for 1953 in these calculations includes the 8.4 million officially reported as indirectly enumerated; the 1964 figure includes an estimated 2.35 million young males omitted from the census, an estimate obtained by correcting understated ratios of males to females from age
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From page 30... ...
The consistency between the calculated annual births and the census enumerations by age was noted earlier; besides, it seems unlikely that respondents in the fertility survey overstated the number of births that had occurred to them. This possibility is especially remote because of the extraordinary agreement (mostly within 1 percent)
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From page 31... ...
One is an epidemiological survey conducted throughout China in 1973-7S in which deaths by age and sex and an age distribution of the population were recorded; the second is another large-scale survey in 1978 covering a sample population of over 100 million, reported in System Engineering and Science Management (Beijing) February, 1980, and the third is a life table constructed from the deaths in 1981 recorded in the 1982 census.
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From page 32... ...
The rate of childbearing for women aged 15 in 1977-78, plus the rate of those aged 16 in 1978-79, plus the rate of those aged 17 in 1979-80, plus the rate of those aged 18 in 1980-81, plus the rate of those aged 19 in 1981-82 equals the average number of children ever born to women reaching exact age 20 in the middle of 1982.6 By an analogous summation the estimated number of children ever her n Pm women of each exact ace from 16 to 65 can be ascertained. Then the average number of lifetime births of women at conventional single-year age intervals (15-16, 16-17, etc.)
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From page 33... ...
In the 10 percent sample tabulation of the 1982 census there are tables listing the number of children ever born alive, and the number of children surviving, for women classified in five-year age intervals from 15-19 to 55-59. For each age group of women the fraction of the children they have borne that were born in each year prior to the census can be determined from the agespecific fertility rates recorded in the fertility survey (which had the same effective date as the census)
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From page 34... ...
A similar calculation can be made for women at exact age 18 in 1982; an average of the fraction in each period for those aged exactly 18 and those aged exactly 19 is a robust estimate of the fraction born in each period to women who were 18-19. Combining such calculations for women aged 15-16, 16-17, 17-18, 18-19, and 19-20, one obtains an estimate of the fraction of the children born alive by women 15-19 whose birth occurred in 1981-82, the fraction whose birth occurred in 1980-81, etc.
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From page 35... ...
Surviving 0-1 1981-82 21.71 20.81 .959 1-2 1980-81 18.93 17.38 .918 2-3 1979-80 19.06 18.27 .959 3-4 1978-79 20.87 19.62 .940 4-5 1977-78 19.63 18.63 .949 5-6 1976-77 20.67 ~ 19.42 .939 6-7 1975-76 22.07 20.42 .926 7-8 1974-75 24.00 21.78 .907 8-9 1973-74 25.86 24.03 .929 9-10 1972-73 26.73 25.09 .938 10-11 1971-72 28.33 25.22 .891 11-12 1970-71 29.88 27.33 .915 12-13 1969-70 29.09 26.50 .911 13-14 1968-69 30.68 28.24 .920 14-15 1967-68 28.28 24.52 .867 15-16 1966-67 26.72 22.74 .851 16-17 1965-66 28.10 25.97 .892 17-18 1964-65 27.11 24.78 .915 18-19 1963-64 31.61 25.78 .815 19-20 1962-63 32.38 28.59 .883 20-21 1961-62 19.46 16.59 .852 21-22 1960-61 14.28 11.20 .784 22-23 1959-60 17.57 14.51 .826 23-24 1958-59 21.08 14.29 .678 24-25 1957-58 26.69 19.45 .729 25-26 1956-57 25.97 18.89 .727 26-27 1955-56 24.88 17.92 .720 27-28 1954-55 26.20 19.67 .751 28-29 1953-54 25.00 18.62 .747 29-30 1952-53 25.52 17.49 .685 30-31 1951-52 24.44 17.36 .711 The agreement between constructed and reported proportions surviving is remarkably close for women aged 25-29 to 40-44. The deviation at the youngest age intervals (under age 25)
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From page 36... ...
The basic agreement between reported and constructed proportions attests to the probable validity of the cohort survival ratios -- not to the validity of individual ratios, but to the average survival of groups of cohorts. Individual survival ratios can be in error because the estimation of fiscal-year births involves an arbitrary element and because of slight deviations of the reported time of birth caused by incomplete adjustment from the lunar to the solar calendar.
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From page 37... ...
The retrospective fertility data provide the basis for constructing an annual series of births and birth rates, which is an addition to the published total fertility rates. The number of births in this series exceeds the number of births listed in official sources by a substantial margin; the fertility data could not have been copied from registers.
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From page 38... ...
The congruence of the proportions dead among children ever born constructed from the calculated birth sequence and the proportions dead reported in the census is powerful evidence of the validity of the birth sequence. It supports, indeed, the approximately equal coverage of the 1964 and 1982 censuses since the constructed survival rates for children born to women aged 40-44 are heavily weighted by the births estimated around 1964.
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