In the United States and Canada, an editor who does this is a copy editor; an organization's highest-ranking copy editor, or the supervising editor of a group of copy editors, may be known as the copy chief. In the United Kingdom and other parts of the world that follow UK nomenclature, the term is sub-editor, commonly shortened to sub ("to sub" is the verb form). The senior sub-editor on a title is referred to as the Chief Sub-Editor.
There is no universal form for the job or job title; it is often written as one word (copyediting) or with a hyphen (copy-editing); the hyphenated form is especially common in Britain. Similarly, the term copy editor may be spelled either as one word, two words, or as a hyphenated compound term.
The copy editor is expected to ensure that the text flows, that it is sensible, fair, and accurate, and that it will provoke no legal problems for the publisher. Newspaper copy editors are sometimes responsible for selecting which news agency's wire copy the newspaper will use and for rewriting it in accordance with house style. Often, the copy editor is the only person, other than the author, to read an entire text before publication. Newspaper managing editors regard copy editors as the newspaper's last line of accurate defense.
A copy editor may abridge a text, by "cutting" and "trimming" it, to reduce its length to fit publishing or broadcasting limits or to improve its meaning. This usually requires omitting parts of the text and rewriting (abridging) the remainder to bridge the gaps created by the omission; some abridgments are only slightly shorter than the originals, but others are much abridged, especially when a literary classic is abridged for younger readers.
Traditionally, the copy editor would read a printed or written manuscript, manually marking it with editor's correction marks. Today, the manuscript is more often read on a computer display and corrections are entered directly.
The rise of desktop publishing means that many copy editors do design and layout work that once was the province of design production crews in print publications. As a result, the skills needed for editing copy have shifted: Technical knowledge is sometimes considered as important as writing ability, though this is more true in journalism than it is in book publishing.
Besides an excellent command of language, copy editors need broad general knowledge of the world at large (for spotting factual errors), good critical thinking skills (to recognize inconsistencies), diplomacy (for dealing with writers), and a thick skin for when editorial diplomacy fails. Also, they must establish priorities and balance a striving for perfection with the necessity to follow deadlines.
Many copy editors have a university degree, often in journalism, English, or communications. In the United States, copy editing often is taught as a college journalism course, though its name varies; news design and pagination also are taught.
In the United States, The Dow Jones Newspaper Fund sponsors internships that include two weeks of training. Also, the American Press Institute, the Poynter Institute, the University of North Carolina at Chapel Hill, and conferences of the American Copy Editors Society offer mid-career training for newspaper copy editors and news editors (news copy desk supervisors).
Most U.S. newspapers and publishers give copy-editing job candidates an editing test or a tryout. These vary widely and often include general items such as acronyms, current events, simple mathematics, punctuation, and skills such as the use of Associated Press style, headline writing, infographics editing, and journalism ethics.
In the U.K., training may be on the job or through publishing courses, privately run seminars, and correspondence courses of the Society for Editors and Proofreaders. The National Council for the Training of Journalists also has a qualification for subs.