a. MIGRATION AND BUSINESS CYCLES
knowledge, but for quantitative measures of seasonal changes in
the numbers employed in construction, we have been forced to rely
upon estimates pieced together from fragmentary data obtained
from various sources. The constituents used in this computation,
together with the final estimate, are shown in Chart 53. The upper
section of this Chart (Fig. A) affords an opportunity to compare
TABLE 57.—INDICES OF SEASONAL FLUCTUATIONS IN CONSTRUCTION IMPLOYMENTa
Average of the twelve months = 100
COMPOSITE INDICES
BuiLping BuiLbing = El a
AND STREEY IMPLOYMENT, Hicaway
LABOR IN SB “wi on HicawAy Si
MoNTH NEw York| © Bumping! ConstrUC-| ND BUILD-STATE
 SIN TION ING CON-STRUCTION

A B C D Bo
Jan. 79.7 75.2 . 76.6 7.2 66.7
Web... 86.6 65.9 77.4 210.0 67.1
Maps, 99.1 68.0 86.9 6.6 75.4
Apr. 100.5 84.7 94.8 | 33.8 86.1
May. ..... 106.7 99.5 105.1 116.9 106.8
ane. 0. 108 2 112.5 111.308 {151.4 117.0
July in 108.6 120.1 114.1 | 187.8 124.6
Ag. ola 109.0 133.5 113. 201 3 2 131.8
Sept... ..... 112.2 116.2 114.6 178.3 123.7
Oct... 104.1 117.8 110.0. 153.8 116.3
Nov... ii. 99.6 110.6 103.7 109.8 104.6
Geil 85.4 96.2 37.5 35.7 80.1
aComputed from the following data:
Series A. Employment in New York building and street labor, 1902-1914 computed from percentage
of trade union members unemployed at the end of each month. New York State Bureau of Labor Statistics,
 Annual Report and Bulletins.
Series B. Percentage change in the number of employees engaged in the construction of buildings,
January, 1922, to December, 1924, Wisconsin Labor Market, monthly issues.
Scries C. Weighted average of Series A, Series B, and employment in 1922 as reported by contractors
in 26 cities, read from curve in Seasonal Operations in the Construction Industries— Report of a Commitiee of
the President's Conference on Unemployment, p. 51.
Series D. Computed from statistics of the number of common laborers employed on Federal Aid
projects in the fourteen states of the New England, Middle Atlantic and East North Central districts in
1922, 1923, and 1924, made available by the courtesy of Mr. J. G. McKay, Chief, Division of Highway
Economics and Transport, U. S. Bureau of Public Roads; and from percentage changes in the number of
employees engaged in the construction of highways in Wisconsin from January, 1922, to December, 1924,
as reported in the Wisconsin Labor Market.
Series E. An average of Series C and D, with weights of (6) assigned to building and (1) to highways.
seasonal indices for the value of contracts awarded (Curve ‘“‘a’’), and
the value of building permits (Curve “b”’), with estimates of employment
 in building, computed from statistics of unemployment
among trade union members in New York building and street labor,
by months, and in Massachusetts building trades by quarters
(Curves ‘“‘¢”’ and ‘‘d”, respectively).