Many sources can complement the TRA survey at the individual level to study specific aspects of the economic and social history of France. Military registers are a good example of such a source. Indeed, they provide considerable information for each individual, including a follow-up of successive residences between the ages of 20 and 46. The information they give comes from two different origins: some of it is collected directly by the army at the time of the review board, while others - particularly changes of residence - are simply recorded from the conscripts’ declarations between the ages of 20 and 46. This information is unique in many respects and does not appear, for instance, in fiscal or marriage records.
The military registers are the direct consequence of a profound reorganization of the French army following the defeat of 1870, which saw the end of a system based on long service by a minority and the establishment of a universal military service. The major innovation is the creation of reserves: conscripts perform a long service (initially twenty years) divided into four main parts, active service (the military service itself), the reserve of the active army, the territorial army and finally the reserve of the territorial army. This was the first step towards an army of universal conscription, which became effective in 1905. In theory, any man is a soldier and can be called up at any time before the end of his military service, which occurs at the age of 46.
In concrete terms, military registers are recorded in the departmental archives that correspond to the military region of residence of the parents when the conscript is twenty years old. For practical reasons, we therefore work at the departmental level and collected all the conscripts whose names begin with the letters TRA in a given department. The aim is to constitute a sample that can be mobilized within the framework of the TRA survey and then match them with the rest of the survey, which allows for mutual enrichment.