I understand that when a client calls a translation company for the first time to fill a need that arises in this context, he or she does not expect to be offered various steps or stages for the service required; instead they simply have a text that they want written in a different language or set of languages. Therefore I think that it may be of interest to explain briefly and in a simple way what the three stages of the translation process are and why each is important.
Translation: rendering a text that is in a particular language into another, transferring information accurately to represent the original document in the target document.
Typically, this step is done with a CAT, or computer-assisted translation, tool (such as Trados or Wordfast), which divides the original text into segments, normally full sentences, so that the translator can translate segment by segment.
The use of translation tools is not only very common in the industry but actually it is essential to work effectively in this field. The little problem it has is that the translator does not have an overall vision of the text.
Editing: in modern parlance, this is used to refer to reviewing what was done in the previous step, i.e., review the translation performed of the original text in the previous step. At this stage, the editor is also working with a translation tool, but his or her task is not so much translation, but revising, segment by segment, that the translator has really made a faithful and accurate translation of the original and has fully understood the text and has not missed any of the information, and that there has not been any omission and any guidelines given by the customer have been followed.
At this stage, although at first the editor works with a CAT tool and cannot see the text as a whole, in the final stages he or she will ensure that the sentences make sense in the overall context of the document or project.
Correction (Proofreading): In this stage, the translation and editing of the text have been done previously, and it is not necessary, in principle, to refer to the original text. This final review focuses primarily on the idea that the translated text read smoothly and sounds natural in the target language, in addition to detecting possible incosistencias regarding capitalization and punctuation. Also, when dealing with documents that have a particular format, he or she may often detect typographical errors, issues related to images and fonts, etc.
Therefore, my opinion as a professional in the industry is that these three steps are essential for obtaining a final product of the highest quality. Each and every one of them are essential for different reasons and any translation services vendor must explain this clearly to the customer so that he is aware of their importance.
(Versión en español: https://www.trustedtranslations.com/traduccion-edicion-y-correcion-2011-05-23.html)