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Note 1. Vital Statistics.
Change of boundaries 1st April, 1934.
The statistics of births, deaths and notifiable diseases for the calendar year are composite
figures combining the records for the first portion of the year prior to the date of
c hange of boundaries with those for the altered area for the remaining portion of the year.
The normal mid-1934 estimate of population for the area as now constituted is 46,680
according to the Registrar-General's estimate, but for the compilation of the rates mentioned
above a working population figure, modified to take account of the fact that the records
do not wholly relate to the entire year, has been fixed by the Registrar-General at 46,693.
The difference is insignificant.
Note 2. Comparability Factor.
The comparability factor is the figure by which the crude death rate of the area should
be multiplied in order to make it, comparable, from a mortality point of view, with the
crude death rate of the country as a whole or with the mortality of any other local area
the crude death rate of which has been similarly modified with its own factor for the purpose.
"The Registrar-General points out that if the populations of all areas were similarly
constituted as regards the proportions of their sex and age group components, their crude
death rates could be validly compared, but as however populations are not thus similarly
constituted their crude death rates fail as true comparative mortality indexes in that their
variations are not due to mortality alone but arise also from differences in their population
constitutions. In order to isolate the mortality factor it is first necessary to remove the
population variable. This is done by means of the comparability factor which has been
evaluated by the Registrar-General as follows:—
The average mortality rates experienced in England and Wales during the
three years 1930/2 divided into 11 sex-age groups have been adopted as the standard
and have been applied to the corresponding sex-age groups in the 1931 census population
of every borough, urban district and rural district in the country. The adjusting
factor now supplied in respect of a given area represents a ratio of the resulting
death rate for the national 1931 census population to the similarly obtained hypothetical
death rate for the said area. The factor may be said to represent the
population handicap to be applied to the area and. when multiplied by the crudo
death rate experienced in the area, modifies the latter so as to make it comparable
with the crude death rate for the country as a whole or with the similarly adjusted
death rate for any other area.
Strictly, the adjusting factor applies only to death rates experienced in the year
1931 on which the several population handicaps have been measured, but population
constitutions change relatively slowly, and save in exceptional circumstances, the
1931 factor may be used for practical purposes until fresh population constitutions
are available for the next census."
The comparable death rate for Southall is therefore the crude death rate (7.49) multiplied
by the comparability factor (1.14) which gives a figure of 8.53.
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