"In order to understand and use the medical data in this dataset, it is necessary to know something about the Civil War pension system. The primary purpose for performing a physical examination on a veteran was to determine the applicant's eligibility for pension assistance. Thus, the form and content of the physical examinations were directly related to how the pension system was administered and the resulting incentives faced by potential pension applicants.

"Civil War pensions were available for veterans with disabilities as well as for deceased veterans' widows, minor children, dependent major children, and parents. Under the Act of July 14, 1862, the first pension legislation specific to the Civil War, the veteran was eligible only for disabilities (wounds or chronic illnesses) received during war-time. The Act of June 27, 1890 changed that requirement and expanded eligibility to include disabilities not directly related to wartime experience. As a result, the number of men on the pension rolls swelled.

"A veteran's pension file often includes information on his birth, residences after discharge from the service, a summary of military and medical wartime experience, and family information, including a listing of spouses and children, whether living or dead. The pension file also includes the veteran's or the surviving dependent's application for a pension and the corresponding record of the Pension Bureau's action. Additionally, the file contains documents in support of the veteran's claim, including affidavits from comrades, neighbors, family members, and physicians. Because a veteran could, and often did, apply for a pension under several acts or submit additional applications because of an increase in disability or dissatisfaction with the Pension Board's decision, files usually contain more than one pension application and record of action; occasionally a pension file includes more than 20 sets of such forms.

"For the EI study, the surgeon's certificate is one of the most important documents found in the veteran's pension file. In addition to providing identifying demographic and military service information, each certificate contains the statement of the claimant regarding his health and disability and some basic physiological measures such as height, weight, pulse rate, and respiration rate. In addition, the examining physicians provided numerical ratings for individual conditions and for disability in general. The bulk of the certificate contains the findings, descriptions, and diagnoses of the examining physicians.

"Examining physicians were charged with a set of detailed instructions, which gave a measure of uniformity to the certificates. However, there was still substantial variation in the content of exams. Part of this variation is due to changes in examination procedures over time, but part is due to idiosyncratic variation in the methods of examining physicians. Of course, the content of an individual certificate was determined primarily by the health of the veteran being examined. Of particular importance was whether or not certain conditions qualified the applicant for pension support. An open research question is determining the extent to which the pensionability of particular conditions determines whether or not they were recorded on the physical examinations. (In many cases, however, conditions were mentioned by examining physicians even if the applicant did not qualify for pension assistance.)"