APA style is a widely accepted format for writing research papers, which specifies such things as the arrangement and punctuation of footnotes and bibliographies. It is promulgated by the American Psychological Association, which is the main scholarly organization for academic psychologists in America.
APA style is officially defined in The Publication Manual of the American Psychological Association, a book of nearly 500 pages now in its fifth edition (ISBN 1-55798-791-2).
The style strikes many authors as imperfect. It forbids authors to number their section headings, a common practice in science journals that permits cross referencing. APA style also requires cited authors to be identified just by their initials, as in "J. A. Smith" rather than "Joan A. Smith", making it hard for readers to look up references. The Manual is long and forces scholars to spend many hours trying to conform to its prescriptions. Finally, APA style is established by a small, unelected editorial committee, who offer users no way to request changes.
Scholarly journals that require APA style sometimes let their authors deviate from it when it would increase clarity.
Although aspects of APA style are resented, it is widely agreed that it serves a useful purpose. Uniform style across journals helps readers absorb material more efficiently. Scholars who experience feelings of uncertainty when writing may find the Manual a useful prop. And the lengthy "political correctness" sections of the manual, though fussy, discourage authors from writing prose that is abusive to women and minorities.