now a large microfilm file, originally consisted of some tens of millions of 3 × 5 cards, one card for each veteran beneficiary. Each 3 × 5 card in VAMI, which was maintained in active use through the early 1970s, contains identifying and VA benefits data for an individually identified veteran. When a muster roll entry could not be matched to an available record folder, an attempt was made to locate the corresponding 3 × 5 card in VAMI and to verify correct identifying data, such as name and MSN. At the same time, additional data, if available, were also recorded: for example, VA claim number or date of death. Using these new identification data, another attempt was then made to find a record folder. Finally, despite the deliberate oversampling of Army and Army Air Corps controls, it was not always possible to find enough unburned records for men of a particular rank, and partially burned records were occasionally ordered. A total of 40,354 military personnel records were abstracted.

In 1989, DNA notified MFUA that the DNA list of CROSSROADS participants reflected substantial numbers of individuals who should not be on the list and omitted many who should be on the list.^l6 The final participant roster used in this study is about 2,500 individuals larger than the 1986 list on which control selection was based. The balance of ranks and ratings in ship types in the existing control pool and the participant cohort were compared and noted to be similar. Since the analysis did not involve pairwise comparisons, we determined that additional controls would not be required.