CONFERENCE BOARD INDEX 57 
articles in 51 cities, is used in the Conference Board’s index. 
By linking these to the index for 22 items secured prior to 1921, 
which, in turn, had increased from 15 articles in 1913, a 
continuous series by months is available since 1913. This 
was not changed originally to a July, 1914 base when the 
National Industrial Conference Board index number of the 
total cost of living was constructed on less precise data than 
at present, and has never been changed since. This is 
because it was felt that for food, perhaps, more than for any 
other major item in the total cost of living, seasonal fluctua- 
tions in price occurred and that, prices being somewhat 
higher in July than a normal average for the year,! the 
latter furnished a better basis for measuring changes over a 
considerable period of time. Had the retail food price 
series been converted to a July, 1914, base, the greatest 
difference would have been found at the peak in July, 1920, 
and there would have been shown an increase of 114.79 for 
food prices over July, 1914, as contrasted with 1199, over 
the average for the year 1913, which is the figure used. 
In the total cost of living this would have made an increase 
since July, 1914, of 102.3%; instead of the regular figure, 
104.5%. These retail food prices are collected by mail each 
month and the Bureau of Labor Statistics furnishes the 
National Industrial Conference Board with the current 
index number as soon as it is completed.? 
The Total Cost of Living 
After the percentages of change in the cost of the large 
aumber of goods and services listed in the preceding pages 
have been ascertained, and have been combined so as to 
show the change in the cost of the five major items since 
July, 1914, these are combined to show the change in the 
budget as a whole. As previously noted, different items 
have a different importance. It is, therefore, necessary to 
give the index number for each item its corresponding im- 
portance or weight in the budget as a whole, by multiplying 
! Prices in July, 1914 were the same as the average for 1914, but 2% higher than 
che average for the year 1913. 
2 See pp. 69-72; 77-79, of this volume for description of the method of collect- 
ng and combining current food prices.