these subjects, called ''volunteers,'' were not asked to undergo a reexamination but instead were identified by matching them against the VA POW exam tracking system, which contains a record for each POW who has undergone the VA's protocol exam. Requests for their already completed examinations were then sent directly to the VA field stations. (More details about this process are provided later in this chapter.)
The issue of volunteers became somewhat more complicated, however, when a site visit by a VA team in August 1989 resulted in a recommendation that volunteers be reexamined. As a result, volunteers were mailed invitations and processed similarly to study subjects who had not been previously examined. The only remaining complication was the possibility that MFUA might receive reports of two examinations for an individual—one done before its invitation and one done afterward. In such cases, only the most recent exam was included in the analyses.
If a study subject had not undergone a POW protocol examination (or later, after volunteers were solicited, even if he had), an invitation was issued by MFUA for the man to undergo examination at a nearby VA hospital. Using addresses on file from previous MFUA follow-up studies or addresses obtained from the VA, the Internal Revenue Service, or a commercial tracing firm (Equifax), MFUA staff mailed subjects as many as three invitations, each of them tracked by a computerized mailing system. If a new address was obtained at any time during the study, fourth, fifth, and sixth mailings were attempted if needed.
Once a study subject agreed to be examined, this fact was logged into the mailing system and used to produce a list of subjects to be scheduled for examination at each VA hospital. Over the course of the study, more than a dozen such schedule lists were sent to VA medical facilities. When the examinations were completed, copies were sent to MFUA, which were then sent out to be abstracted, coded, and computerized by trained nosologists under MFUA's contract with GRG Associates, a local subcontractor.
Much of the invitation letter process was automated, and a computerized mail system developed in an earlier POW study was used to generate and print mailing labels and keep track of mailing dates and mail status information. The complete mail package included a cover letter, a postage-paid envelope, and a response form on which the subject indicated his willingness to participate and provided contacting information, such as his home or work telephone number (see Appendix A).
When responses were received from the mailing, they were logged into the mailing system. In most cases the response (or lack of it) was easy to categorize, and the following codes were simply entered into the system: