100 COST OF LIVING IN THE UNITED STATES 
in church contributions and dues were estimated at definite 
percentages;! in 1921 and 1922 these were not listed; in 
1923, 1924 and 1925, only insurance and tobacco are men- 
tioned.? In 1925, automobiles and radios are considered.? 
Having found the percentage of change in cost of each of 
these various sundries items on a specified date, and its new 
unit cost, each of these is in turn reduced to a relative of its 
1913 cost. After that the procedure involves weighting and 
additional arithmetical processes used for the other major 
items to get the index for sundries as a whole. 
The Total Cost of Living 
Having found the increase in the cost of each major item 
n the family budget since 1913 by the methods described 
n the foregoing pages, the increase in the total cost of living 
since 1913 is found by the same formula as that used by the 
National Industrial Conference Board and illustrated on 
page 58 of this volume. That is, the index number for each 
major item is multiplied by its respective weight in the 
budget and these products, added together, are divided by 
the sum of the weights. 
SuMMARY 
The method of collecting and combining data for the cost 
of living index number of the Massachusetts Commission 
on the Necessaries of Life is shown in the tabulation on the 
following page. 
- I4id., 1920, p. 108. 
 [bid., 1923, p. 240; ibid., 1924, pp. 135, 136; ibid., 1925, p. 59. 
s Thid., 1925, pp. 59-60. These are not mentioned in the list of sundries items 
and no weights are given. See p. 95 of this volume.