An "error" is philately usually refers something that has gone wrong in the production of a stamp: the wrong or missing colors, misperforations, inversions, and things like that. Such errors are relatively rare and therefore stamps with such errors are expensive. However, there is another kind of error that is neither so rare nor so expensive. It is the design error. In the case of map stamps they include incorrect coordinates, mistakes in spelling, incorrect geography, political and historical errors, and other similar matters. This section is concerned with those errors.
     The American Topical Association includes “Design Errors”  with “ghosts” under “Oddities” in the section titled “Unplanned Varieties (EFOs)” in their publication, Elements for Thematic Exhibits.