The definitions used are discussed in the text but something needs to be said about the difficulties encountered in trying to apply these definitions in the particular sources from which names of men were obtained.

In the case of quoted public companies the selection of men was easy. Those listed as chairman, vice-chairman, deputy-chairman, managing director, joint-managing director or general manager (and a director) in the Stock Exchange Official Yearbook and its predecessors back to 1865 were included.

Discovery of names of men at the head of non-quoted limited companies presented more problems. Since 1901 limited companies have been required to submit lists of their directors with each annual report and to report any changes in the board. Until 1919 they were not required to state which directors were officers nor to give the principal occupation of the directors. In some cases chairmen and managing directors were named, but in others one must make inferences as to which men were executive directors. Usually, lists of directors were submitted with the senior man on the board at the top and the most recent appointee at the bottom. If, from the context, such appears to have been the practice of a particular firm, the first man named at sample dates has been taken, as well as any other directors described as ‘steel manufacturers’ or resident at or near the works.