Translation expert witnesses may opine on document translation and medical interpreting. Here, the American Translators Association explains that translation is not a commodity and offers standards for buying a non-commodity.
#3 The intended readers.
Are you targeting teenagegamers, genetic researchers, patent agents or simply anyone who might stumble upon your website?
#4 The purpose of the translation.
Sometimes all you want is to get (or give) the general idea of a document (rough translation); in other cases, a polished text is essential.
#5 The regional variation of the target language.
Are your readers Mexicans in Monterrey or Spaniards in Seville? Both speak Spanish but it’s not the same Spanish.