|A back-translation involves re-translating a document back into its original language. The purpose is to verify whether a translation's meaning has been accurately conveyed. To do this, a back-translation is performed by an entirely separate translator.
Is this step necessary? For important projects, yes. Back-translation is an extra layer of quality assurance that brings greater peace of mind to any project. It is especially recommended for important material where the loss or gain of significant capital (even life) depends on correctly translating its proper meaning. Such material includes scientific, medical, legal, technical, and localization projects where conveying their proper meaning is absolutely critical.
A back-translation will not be an exact replica of the original text; replication in this manner, between two translators working independently, is impossible. A back-translation is intended only to ensure that a translation's original meaning has been correctly conveyed.