MIGRATION AND BUSINESS CYCLES
discussed, male immigration is of greatest significance for our
purpose, and, consequently in the more detailed analysis based
upon quarterly and monthly data, we have, where convenient,
made use of the statistics of male immigration rather than of the
totals for both sexes.
Adjustment for a Variable Seasonal.
In analyzing the fluctuations of quarterly male immigration, the
typical seasonal element has been, so far as practicable, eliminated
and the adjusted fluctuations expressed as deviations from a twenty-CHART
 12
CYCLES IN QUARTERLY IMPORTS OF MERCHANDISE AND IN MALE
IMMIGRATION: 1868-1889
Adjusted for typical seasonal variation
Unit= one standard deviation
+2.0-i

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«Numerical data in Table 19.
eight quarter moving average. In thus correcting for seasonal
variation, allowance was made for a seasonal influence which varies
at different stages in the cycle, in order to conform to the fact,
revealed by examination of the raw data, that the seasonal fluctuation
 experiences somewhat regularly a damping down in the depression
 period of each cycle. In other words, the seasonal is itself
subject to a cyclical variation.
Inasmuch as during most of the period prior to 1890 quarterly
figures on production or employment are not available, we have
used quarterly statistics of merchandise imports as a rough measure
of industrial activity in the years 1868 to 1889. The import figures,
like the immigration data, have been adjusted for a changing normal
seasonal variation and expressed as deviations from a twenty-eight
quarter moving average.

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