Report of the President's Commission on the Assassination of President John F. Kennedy

General Principles of Handwriting Identification

General Principles of Handwriting Identification Questioned document examination rests on the principle that every person’s handwriting is distinctive because mental and physical writing equipment differs between individuals, so each person develops unique writing habits. According to Cole, handwriting identification is confirmed by long observation of specimens and by formal responsibility for decisions subsequently tested against field-investigated results. Hand printing is subject to the same principles. Not every letter serves as a basis for identification, since most writing begins from standard copybook forms and is distinctive only insofar as it departs from them; variations within a single document are also normal. An identification requires a sufficient number of corresponding distinctive characteristics and a general absence of distinctive differences. Imitation by a forger is very remote, because the forger typically draws rather than writes, producing defects such as tremor, waver, patching, retouching, noncontinuous lines, and pen lifts in awkward places. To make an identification, the examiner first studies the questioned writing independently, then studies the known standards, and finally conducts a detailed comparison considering letter forms, proportion, pen pressure, and letter connections. The standards used by Cole and Cadigan included a wide variety of documents known to be in Oswald’s handwriting, such as payroll endorsements, employment and passport applications, ACLU membership and library card applications, and letters to government agencies.