Identification of an industrial cohort and verification of its completeness using a complicated system of plant records

The published literature on occupational mortality studies seldom describes the manner in which cohorts were assembled and efforts made to ensure that all, or nearly all, eligible persons had been enumerated. Researchers must struggle unassisted through a morass of plant records, often not knowing how to utilize important sources of information to the fullest extent. This paper describes the identification of a cohort of over 8,700 foundry workers and the verification of its completeness using existing plant data sources. By understanding the techniques for manipulating data sources in this investigation, researchers may gain insight into the use of materials available to them.