COST OF LIVING INDEXES COMPARED 103 
duties of the Commission on the Necessaries of Life in 
Massachusetts possibly have tended to hold down prices 
in that state to some extent! There may be other reasons, 
also, to account for the relatively smaller increases recorded 
in Massachusetts than. for the country as a whole. The 
significant feature of the Massachusetts index number is 
that it is the only series which affords a measure of changes 
in the cost of living over a period antedating 1913, since by 
linking these figures to other Massachusetts data, estimates 
of changes in the cost of living in that state since 1901 may 
be made.? For the period for which other data are lacking, 
namely, 1901 to 1913, it is probable that the Massachusetts 
figures underestimate but slightly, if at all, the situation for 
the country as a whole? For the period since 1919, they may 
be slightly lower than would have been the case had it not 
been for the administrative activities of the commission, 
but for the most part these differences are very small. 
The two series which purport to measure changes in the 
cost of living for the country as a whole show results at 
times so different that the validity of either has been ques- 
tioned. A detailed explanation of the differences is, there- 
fore, highly desirable for the purpose of reconciling them. if 
possible.* 
It should be recognized at the outset that although the 
results of attempts to measure changes in the cost of living 
are expressed in exact mathematical terms, the nature of 
the problem and the basic data of necessity are such as to 
require a certain breadth in the interpretation of results. 
Thus, as will appear later, it is perhaps more remarkable 
that the two series have been as close together as they have 
than that they are not exactly in line. 
The differences between the two series up to 1918 were 
. 1 The commission took up its duties August 1, 1919; the numbers in the cost of 
living series prior to that date were estimates of price changes not affected by the 
administrative activities of the commission. 
? See Table 5 (p. 89) and Chart 3 (p. 88) of this volume. 
$ The retail food price series of the Commission on the Necessaries of Life runs 
about 29, lower for Massachusetts than that of the United States Bureau of Labor 
Statistics for the country as a whole. 
* For a comparison of the two series from a different point of view see an article 
by Elma B. Carr, formerly an agent of the United States Bureau of Labor Statistics, 
n the Journal of the American Statistical Association, December, 1924. op. cit.