We have established again and again that the ‘quality’ of a translation is very hard to measure absolutely. Beyond certain objective indices that everyone can agree on (linguistic mistakes, correct use of industry terminology, correct use of terminology specified by the client) it very often comes down to a question of (subjective) preference.
There are several ways, however, that you can assess the quality and impact of a translation, beyond the text itself.
They fall into four broad categories:
1.) Whether the translation responds to your specifications. These may be fundamentally your subjective choices, but in the moment that you communicate them clearly to your language service provider (LSP) they become objective! Make sure that your LSPs work following the glossaries and style guides laid out in your localization kit. This also makes it easier to compare the work of different LSPs.
2.) Translator benchmarks. The translation industry is cost-driven and unregulated. If an LSP actively seeks external validation, this can be taken as a good sign. You should thus check which translators´associations they belong to. A very important consideration is the ISO: 9001 certification speaks volumes for about an LSP’s commitment to providing outstanding service.
3.) Vertical industry metrics. Many industries are promulgating their own global standards for translation and globalization. The Society for Automotive Engineers, for example, recently developed the J2450 ´Quality metric for language translation of service information’, and General Motors now specifies J2450 in its contracts.
4.) Test it on humans! The ultimate test of how successful a translation has been is if it does what it was supposed to do. In the case of marketing collateral, show it to an unbiased member of the target demographic. If it is a technical manual, run it past an engineer! This is the best way to streamline the translation process, as it will enable you to communicate better what your needs are to your LSP. There must be a continual feedback loop between the two parties. This is the best way to guarantee a lengthy and productive relationship.