DETERMINATION- OP EFFICIENCIES 3l9
the subjects of study are selected as above stated, I
have found the error of sampling, though appreciable,
to be negligible for the purpose in hand.
328. The efficiency of supply of labor can be approximated
closely enough in the course of a few days,
by walking through the plant at various times during
working hours, counting the number of workers who
are idle at the moment of passing them, and comparing
this with the number of workers present. In determining
the result, allowance must be made for the
amount of rest during working hours, which is necessary
to obtain the maximum of efficiency of labor as
the final product. See Article 208.
Suppose that, on an ordinary class of work, out of
one hundred male workers present, twelve are observed
to be idle at the moment when the observer
passes. Since 10 per cent should be resting at any
moment, and thus only ninety men should be at work,
the efficiency of supply of labor is 88-r-90=98 per cent.
329. The efficiency of price of labor can be obtained
by comparing the pay-roll of the plant with the local
market rates of wages for workers of the same class.
In so doing the eiïect of the application of the principle
of Efficiency Eeward must be considered, because
maximum savings will not be effected unless the workers
are given a share of them by the application of
this principle. For example, let the average hourly
wage rate of the workers be 20 cents, while the average
market rate for their class of labor is 22 cents.
We shall have to count, not only on paying them 22
cents per hour, but on paying them an efficiency reward
as well. This is more fully discussed in Chapter
XIV; but may here be assumed with sufficient accuracy
at 20 per cent of the hourly rate. Efficiency re-