FOREWORD
of the Department of Anthropology in the American Museum of
Natural History, and Dr. Robert M. Yerkes, Chairman of the Research
 Information Service of the National Research Council, and
also of the Committee.
In preparation for their work, the Committee called a conference
of anthropologists, biologists, economists, psychologists and sociologists
 interested in various aspects of migration. After surveying
the field and considering numerous suggestions, the Committee
decided that it could render the best service by promoting work
upon certain fundamental problems which must be solved as preliminaries
 to the scientific study of the characteristics, causes and
effects of migration. Each problem was referred to a group of
technically qualified investigators. The various groups worked in
severalty, by whatever methods were best adapted to their tasks.
Meanwhile the Committee gave the program as a whole such unity
as was possible, by holding occasional conferences, in which all the
cooperating investigators took part. The scope of the work undertaken
 is indicated by the following partial list of topics: the possibility
 of developing reliable measures of the psychological characteristics
 of different ethnic groups, the influence of race upon pathology,
 the behavior of physical traits in race intermixture, and
the sources of information concerning the causes of migration
available in Europe. To defray the expenses incident to these inquiries,
 the National Research Council obtained a grant from the
Laura Spelman Rockefeller Memorial.
Among the problems which the Committee on Scientific Problems
of Human Migration thought important to investigate was the
“Shortage and surplus of labor in the United States in its relations
to immigration and emigration.” This problem was referred to
the National Bureau of Economic Research.
Before it received this request to cooperate in the migration program,
 the National Bureau had begun a series of researches into
the phenomena of business cycles. One report within this field,
made at the request of a committee of President Harding's Conference
 on Unemployment, had already been published under the
title, Business Cycles and Unemployment. A second report was on
the point of appearing—Employment, Hours and Earnings in Prosperity
 and Depression, by Dr. Willford I. King, Dr. Leo Wolman’s
monograph on The Growth of American Trade Unions, 1880-1923,
was then well under way, and has since been printed. Dr. Frederick

6