CONFERENCE BOARD INDEX 29
base period of the Board’s series is, therefore, somewhat
broader than is apparent on the surface.
With July, 1914 as the base period, a number was com-
puted in June and November, 1918, and in March, July and
November, 1919. In 1920 and in the years following, num-
bers have been constructed each month. This series, together
with interpolations for July, 1915, July, 1916 and July, 1917,
for which dates little exact information is available, constitute
a continuing measure of changes in the cost of maintaining
substantially the pre-war standard of living! for families of
small and moderate means. It is based on retail prices of
goods and services representative of a complete family
budget, combined in such a way as to give proper weight to
each item in proportion to the expenditures therefor by
wage earners’ families before the war. Until December,
1925, the figures collected for months other than March,
July and November of each year were on a somewhat more
limited basis, as regards both localities covered and number
of reports, than were those for the above mentioned dates.
The December, 1925 figures are on the same basis as those
for March, July and November, and it is now planned that
in the future the index numbers for all twelve months will
be strictly comparable. In the present volume the more com-
prehensive figures will, however, be discussed separately from
the others.
. The series based on the more comprehensive surveys is
given in Table 1 for all dates for which numbers are available.
Chart 1 shows the same results in graphic form. The method
of collecting and combining prices of the articles entering
Into the major items food, shelter, clothing, fuel and light
and sundries, and of the major items themselves to obtain
the change in the total cost of living, is described in the pages
which follow. The detailed results are presented and ana-
lyzed in Chapter VI.
. At the time of the Board’s first estimate of the increase
in the cost of living, great speed was necessary and there
were no models to follow, either as to basic standards or
methods of collecting and working out the data. For a
' It is recognized, of course, that customs and goods available for consumption
thange, but so far as possible every contingency here is protected.