demographic yearbook annuaire demographique 1951

certain to indicate improvement in coverage rather than a
rise in fertility or mortality. Rising stillbirth ratios are also
likely to indicate improved registration. Furthermore, temporary
measures, such as the removal of registration fees in
order to encourage registration, may cause the numbers to
rise sharply in certain years. Where tabulations include delayed
registration, the fluctuations are particularly violent.
When factors of this type are known to be operating, they
are noted in the tables.
Another source of variation in the statistics of births and
deaths lies in the definition of births, deaths and stillbirths.
Almost universally births and deaths are so defined as to
exclude stillbirths. But variation in the definition of stillbirths
results in some variation in the definition of live births
and deaths. From the viewpoint of the accuracy and comparability
of stillbirth statistics, it is necessary to establish a
uniform and definite criterion differentiating between stillbirths
and other products of human gestation which have
not yet reached the stage of development justifying their
inclusion as stillbirths. However, from the viewpoint of
accuracy and comparability of live birth and death statistics
it is more important to establish a uniform and definite
criterion differentiating between stillbirths and live births.
Variations in registration procedure may have an important
eflect in this regard. The legal time allowed for registration
of a live birth varies from twenty-four hours to one year or
more. Infants who die shortly after birth are therefore sometimes
omitted from the birth registrations, and because the
deaths were almost immediate, they also fail to be recorded
as deaths.
In several countries, the definition of a stillbirth for
statistical purposes is broadened to include those infants,
born alive, who die before registration of birth. These births
of infants dying before registration are therefore excluded
from the live birth statistics and their deaths from the death
statistics. As a result, stillbirth ratios are exaggerated and
general birth and death rates are understated to some degree.
The infant mortality rate is also affected, for, although
both the components of the rate are deficient by the same
absolute amount, the rate nevertheless tends to understate'
actual mortality because the deficiency is proportionately
greater in relation to the number of infant deaths than in
relation to the number of births.
Problems of comparability stemming from these sources
will be lessened as international standards of definition and
classification are developed. Some progress has already been
made in the work of the Expert Committee on Health Statistics
of the World Health Organization which has recommended
uniform procedures for adoption by the various
countries.
As the information given in the code columns and in the
footnotes makes clear, some of the material presented in the
tables is useful, not as a measure of actual levels and changes,
but rather as an indication of where registration systems are
in effect and as a record of progress toward a more complete
registration of vital events. The coverage for Africa is par­
31
ticularly spotty, being largely confined to data on the
"European" population with, as a rule, only a few partial
statistics for the indigenous segments. Similarly, the coverage
is uneven and the statistics incomplete for much of Asia
and for parts of Latin America.
For the computation of the annual rates shown in various
tables, the midyear population was taken as a base whenever
available. Otherwise, averages of year-end estimates or
figures for other dates within the year were taken. The reIatively
few cases in which the rate is based on other than the
midyear population are not noted in the tables since the
effect on the rate is regarded as negligible. In so far as
possible, the vital data relate to the de facto population and
rates are based on the de facto population. The population
base does not in all cases agree precisely with the vital
statistics as to the inclusion or exclusion of certain groups
(armed forces, prisoners ofwar, residents abroad etc.). These
minor variations probably have little effect on the rates,
except for certain areas during the war. Rates are not shown
where the numbers involved are so small that the rates are
subject to severe chance fluctuations or where known differences
between the coverage of vital data and the coverage of
population data are believed sufficient to invalidate the
rates. Except for the data in table 5 and table 12, all rates
were computed in the Statistical Office ofthe United Nations
from official statistics.
BIRTH STATISTICS
Natality statistics are presented in tables 5 to 9. Unless
otherwise noted, stillbirths are excluded, illegitimate births
are included and each member of a multiple birth is counted
separately.
Table 5 presents a summary of crude birth rates for 64
areas during the period 1905 to 1930. These data are average
rates for the periods 1905-1909,1911-1913,1921-1925
and 1926-1930. They were taken from the League of Nations
Yearbook, the data for the first period from the 1928 issue
and the remainder from the 1942-1944 issue. Unless otherwise
noted, the rates refer to the territory of 1937 rather than
to the present territory. In spite of the limitations to comparability
that arise from boundary changes subsequent to
1937 and from the fact that the basic data have not been
systematically revised and the rates recomputed in the light
of more recent information, it is believed that these statistics
are sufficiently reliable and comparable to furnish some
indication of fertility levels and trends from the early years
of the twentieth century up to the period covered by the
more detailed tables. It is not likely that much additional
information has become available since 1905-1930 statistics
were last compiled by the League of Nations.
Table 6 gives the number of births reported, by calendar
years, for the period 1935 to 1950 for 144 areas, and table 7
gives the corresponding annual crude rates (along with rates
for 1930-1934) for 129 areas. The geographic coverage of
the latter table is somewhat less than that of the former because,
in a considerable number of cases, appropriate population
estimates for the computation of rates were not available.
The crude rate is the number of births per 1,000 persons
in the midyear population or, in a minor number of
cases, the population at some other date during the year.
In general, the population totals on which the rates are
based are those presented in table 3. Some exceptions occur
when rates are shown for only a part of the population or
when the years for which data can be presented are only
those years already covered in table 1.
Crude birth rates are a measure of gross additions to the
population through natality, but, because of differences
between countries in the age and sex composition of the
population, these rates do not reflect differences in the frequency
of births among men and women of child-bearing
age very precisely. They give only a general idea of trends
over time and of differences between countries in levels of
fertility.