A text that has already been translated is translated in the opposite direction to its original language. Its purpose is to confirm that the translation you are about to use is accurate. The process usually consists of 3 steps:

• A new translation of the translation already made back into its original language;
• Comparison of the new translation with the original text;
• Analysis of any significant differences between the two texts.

This type of translation is usually applied to special purpose documents, e.g. questionnaires, survey forms, presentations, promotional videos and the like, where information will be gathered or a reaction based on translated texts will be expected. Often, back translation is used by government institutions, companies and corporations in fields such as medicine, pharmaceuticals, high technology, etc. It is generally preferred for critical, high-risk content where accuracy of translation is paramount and any errors can have serious consequences.