ESTIMATES OF NET MIGRATION IN THE UNITES STATES, 1870-1940.

The two outstanding studies of historical trends of internal migration in the United States were both made some years ago. C.J. Galpin and T.B. Manny made their study in 1934 and C.W. Thornthwaite's study was also made in that year. Both of these studies used state-of-birth data from the Census. The present study, for which this paper is merely a progress report, is using the survival method for estimating net migration. In this method survival rates are computed for each age-sex-color-nativity group for each decade. These survival rates are applied to the number present at the beginning of a decade, in order to get an expected number present at the end of the decade. This expected number is compared with the observed number present at the end of the decade and the difference is considered to be due to net migration. Obviously the accuracy of this method is determined by both the accuracy of enumeration of the population and the accuracy of the survival rates. Since enumeration is generally fairly accurate and since there is little one can do about errors here, efforts are turned to the computation of survival rates.