60 COST OF LIVING IN THE UNITED STATES 
that the numbers for all months will be on an equally com- 
prehensive basis. 
Until April, 1922, in order to get the figures out promptly, 
the prices were as of the first, rather than as of the fifteenth 
of the month, and the retail food price index number of the 
United States Bureau of Labor Statistics for the fifteenth 
of the preceding month was used. Beginning in April, 1922, 
all were put on the basis of prices on the fifteenth of the month 
and the retail food price index number for the same date was 
used. The figures given in Table 3 have been corrected from 
+he figures originally published, to include the retail food 
price index number for the month to which the number re- 
lates, rather than the preceding month.! 
SuMMARY 
The tabulations on pages 61 and 62 summarize the details 
siven in the present chapter as regards sources of informa- 
tion, localities covered, number of items and method of 
sathering and combining current price data, used in making 
up the National Industrial Conference Board index numbers 
»f the cost of living. 
1 For original series. see Research Report No. 49, 0. ¢it., p. 33.