characteristics of different kinds of work, which comparison is declared
to be unobtainable. Secondly, it may be said that in order to fix such
wage differentials as are reasonably certain to accomplish the ends for
which they are set, it will be necessary to have a precise knowledge of
many facts and forces. This knowledge may be declared to be
unobtainable.

No simple or very final answer can be returned to these doubts. It must
be admitted that it will always remain difficult to compare occupations
except in general descriptive terms. The relative training and talents
required for different kinds of work, and the relative demands made upon
the individual by different kinds of work will always remain, to a great
extent, a matter of opinion. It is also true that only a general
knowledge can be obtained of the factors governing the supply of any
particular sort of labor at a given time, and the probable effect of any
wage change upon that supply. The differentials which would be
established from a consideration of such material could not claim to be
more than a practical approximation to the differentials which would
carry out the intention of the policy.

Still, scientific method could be pushed further than it has been in the
comparison of occupations. The statements of the various interested
parties would be a valuable guide in the estimate of occupations.
Furthermore, only the major relationships between occupations would have
to be taken into consideration. For example, if the question at issue
was whether the wages of miners were too low as compared with wages in
other industries--that is to say, whether a demand on the part of the
miners for an improvement in their relative economic position was
justified--only the most important of mining occupations would have to
be taken into account in reaching a decision. There would be small risk
of error in applying a decision, based upon a study of the work
performed and of the income received in the most important mining
occupations, to the less important mining occupations also. And indeed
such would prove probably the only practicable policy. Furthermore,
revision of the existing differentials would be undertaken only when the
case for revision seemed definite and clear. As for example, it was
clear in England before the war, that railroad labor was underpaid; or,
as was clear to the whole of the recent President's commission on the
wages of coal miners, that the wage