Key points are not available for this paper at this time.
Karen Oppenheim Mason, William M. Mason, H. H. Winsborough, W. Kenneth Poole, Some Methodological Issues in Cohort Analysis of Archival Data, American Sociological Review, Vol. 38, No. 2 (Apr., 1973), pp. 242-258
Mason et al. (Sun,) studied this question.