1957 - United Nations Statistics Division

introduces non-comparability, the direction of the bias
depending on which component is more completely registered.
Variations in the statistical definition of a live birth
and a stillbirth have been discussed on p. 26. It may be
noted that data for Guadeloupe and Martinique could
be used to evaluate the effect of this factor.
Differences in the age classification used may also introduce
lack of comparability in the rates. For neo-natal
deaths, the effect of these variations may be evaluated
using rates for Austria, Finland, and Norway, which are
available tabulated both ways.
The method of reckoning infant age at death, i.e., time
elapsed between date of birth and date of death (in
minutes, hours, days as appropriate) versus the method
of reckoning to the nearest day, disregarding hours, introduces
a source of non-comparability. This factor is particularly
troublesome in determining the number of
deaths under I day and those occurring between I day
and I week; care should be taken to consider this in
analysing rates-especially in these age groups.
Table 14
Cause-of-death statistIcs, both numbers and rates, are
set forth in Table 14. Because this issue of the Demographic
Yearbook is devoted primarily to mortality statistics,
the trends of deaths by cause from 1952 to 1956
have been set forth in Table 14. For many countries, data
for only one or two years are available but, for a number,
this table provides continuity between the information
contained in the 1951 "mortality" volume and currently
available series.
The classification of cause of death used is the "Abbreviated
List of 50 Causes for Tabulation of Mortality"
of the 1948 (sixth) revision of the international list of
causes of death, known as the "International Statistical
Classification of Diseases, Injuries, and Causes of
Death".32 Data tabulated according to previous revisions
of the list are not included.
Coverage: A total of ll2 geographic areas appear in this
table. The criterion used to determine whether or not
data for an area should be included was availability of
statistics classified according to the "Abbreviated List"
mentioned above. Even though some statistics by cause
were known to be inaccurate because of lack of medical
certification, they were retained in the table unless they
were eliminated on the basis of the above criterion. This
was done because of the inability to know where to draw
a line between "accurate" and "inaccurate" and because
even a cause distribution based on poor diagnoses yields
some information as to relative importance of one cause
and another within the distribution. It should be noted,
however, that rates have been computed only on a
selected number of these distributions (see Rate computation
below).
Several countries not shown in the table (for example,
East Germany) had made available distributions of deaths
by cause classified according to either a national scheme
or one of the revisions prior to the current (1948) inter-
32 Manual of the International Statistical Classification of Diseases,
Injuries, and Causes of Death; 6th revision of the International Lists
of Diseases and Causes of Death adopted 1948, vol. I (World Health
Organization, Bulletin, Supplement I), Geneva, 1948.
32
national classification. Since comparability cannot easily
be achieved between classifications, these distributions
were omilted. 33
In some cases, the only data available by cause are
deaths "medically certified"; these distributions are included
in Table 14, with an explanatory note.
Rate computation: Rates by cause are the number of deaths
in each cause group per 100 000 persons in the midyear
or other annual estimate of population. The rate for all
causes combined is, therefore, the sum of the cause-group
rates, and has a magnitude 100 times that of the crude
death rate shown in Tables 8 and II.
Rates are computed only for those distributions in
which the total number of deaths from all causes numbered
at least 1,000 and those classified as due to senility
and ill-defined or unknown causes (B45) did not exceed
25% of the total. If this cause of death (B45) accounted
for over 25% of the deaths, numbers of deaths for each
cause were shown but rates were not computed. This
selection is based on the premise that if 25% of the deaths
have been coded as due to senility, undefined or unknown
causes, the other 49 causes in the List must be understated
to a marked degree. The limit has been placed
deliberately high; it might better be at 10% to exclude
all "poor" data. Moreover, it must be admitted that this
criterion fails to consider the equally indicative percentages
in B46, "all other diseases"-a category which often
accounts for an inordinately large proportion of the
whole.
In one or two instances it may be noted that the rate
for all causes does not agree exactly with the corresponding
total death rate shown in Tables 8 or II, and these
are noted in Table 14. This lack of agreement is due
primarily to differences in the total of deaths tabulated
by cause. Such differences might be the result of the omission
from the tabulation by cause of reports which were
delayed unduly or the exclusion from the cause distribution
of those infants born alive who died within 24 hours
of birth or before registration, and who, therefore, were
registered as "stillbirths". In several countries, tabulation
procedures have been devised to separate these pseudostillbirths
from true stillbirths and to incorporate them
into the total deaths, but even in these cases there is no
way of knowing the cause of the death, since it is not
registered.
Limitations: Cause-of-death statistics, which are of the greatest
importance from both the public health and demographic
point of view, are unfortunately subject to many
defects in addition to those already described as limiting
the international comparability of death statistics in
general. These additional limitations arise mainly from
differences among countries in the quality, availability,
and efficiency of medical services, certification procedures,
and coding practices.
The introduction of the 1948 Revision of the International
Lists of Diseases and Causes of Death brought
with it major changes in coding procedures and rules, as
33 For comparability of statistics of cause of death according to the
fifth and sixth revisions of the International List, see Comparability
of Statistics of Causes of Death According to the Fifth and Sixth
Revisions of the International List (World Health Organization,
Bulletin, Supplement 4) , Geneva, 1952.
34 [Footnote suppressed.l