1957 - United Nations Statistics Division

CHAPTER II. TECHNICAL NOTES ON THE STATISTICAL TABLES
SOURCE OF DATA
The statistics presented in the Demographic Yearbook
are official data. The population and vital statistics have
been assembled by the Statistical Office of the United Nations
from data transmitted monthly and annually by the
national statistical services or appropriate governmental
offices of over 200 areas, supplemented when necessary by
data from official publications. Migration statistics are
those assembled by the International Labour Office from
official national sources, and the tables on this subject
have been prepared by that Specialized Agency.
To establish comparability in so far as computation
procedures are concerned, all rates and ratios (except
life-table functions and a few other exceptions noted in
the tables) have been computed in the Statistical Office
of the United Nations according to the methods described
below. The populations used for the computation of rates
are censuses or estimates published in this or previous
issues of the Yearbook.
In cases where differences are observed between data in
this volume and those published in previous Yearbooks,
statistics in this issue may be assumed to be revisions received
in the Statistical Office by 1 November 1957.
SCOPE OF DATA
Geographic and ethnic coverage
In accordance with the original plans, the geographic
coverage has been made as extensive as possible, within
stated limits. This means that, in general, the Yearbook
shows in each table national statistics for as many countries
and territories as provide them. Moreover, in the
absence of national coverage, data relating to ethnic segments
of populations, "registration areas", and even individual
cities have also been included, wherever these
statistics of more limited scope were deemed of sufficient
utility and interest to warrant publication. The publication
of these data does not, however, indicate that a value
judgment has been made as to their accuracy. Rather, the
adoption of this maximum geographic coverage is made
possible because of the availability of evaluation codes,
described on pp. 16 and 24. However, it should be noted
that most data for sub-national segments--either geographic
or ethnic-are shown in smaller type as a warning
to the reader that they are less than national in scope.
Table 1 is the most comprehensive, showing population
and area for every country-sovereign and non-sovereign
-and thus making it possible to present in Table 2 aggre-
INTRODUCTION
gates for the world and 14 geographic regions. In succeeding
tables, the geographic scope tends to decrease as the
complexity of the table and the subject-matter increases
because fewer countries make these tabulations. It should
also be noted that rate tables are naturally somewhat
more limited in geographic coverage than tables of absolute
numbers. Although no consistent criteria have been
used, crude rates were usually not computed on frequencies
less than 15, nor age-specific rates on a distribution
which totalled less than 50. In tables showing death rates
by cause, specific for age and sex, a minimum of 1,000
deaths has been used as the criterion for rate computation.
Territorial
As a general rule, all statistics set forth in the Demographic
Yearbook are for the territory within the "present"
(1957) boundaries of the geographic unit specified.
\Vhere a comprehensive definition of the statistics appears
to depend on clarification of "present territory", a brief
description of salient points has been set forth in Table l.
Whenever the territory to which data relate is other than
'the present, footnotes have been used to describe the way
in which the geographic constitution of the reporting
area differed from that within present boundaries. The
only exception to this footnoting policy occurs when
data are for the year in which the latest boundary change
took place. In order that no confusion may result in these
cases, explanatory footnotes have been included, even
though the coverage conforms to "present territory".
13
Population
In assembling national statistics for publication, the
aim has been to obtain data for the present-in-area or de
facto population, rather than for the habitually resident
or de jure. Thus, unless otherwise noted, population and
vital-statistics series include data for nationals and aliens,
jungle tribes, aborigines, nomadic peoples, displaced persons,
internees, refugees, and the like.
It should be noted, however, that when the required
statistics were available, population figures have been
adjusted or "modified" to include national armed forces
and diplomats stationed outside the country, and to exclude
alien armed forces, diplomats, and enemy prisoners
of war stationed in the area. For clarity, such adjustments
are explained in the tables both where the population
figures are shown and, if applicable, where these figures
are used in the computation of vital-statistics rates. For a
complete explanation of the adjustment, see p. 15.