Outlining an original, discourse-based model for translation quality assessment that goes beyond conventional microtextual error analysis, Malcolm Williams explores the potential of transferring reasoning and argument as the prime criterion of translation quality. Assessment through error analysis is inevitably based on an error count - an unsatisfactory means of establishing, and justifying, differences in quality that forces the evaluator to focus on subsentence elements rather than the key messages of the source text. Williams counters that a judgment of translation quality should be based primarily on the success with which the translator has rendered the reasoning, or argument structure. Six aspects for assessment are proposed: argument macrostructure, propositional functions, conjunctives, types of arguments, figures of speech, and narrative strategy. Williams illustrates the approach using three different types of examples: letters, statistical reports, and argumentative articles for publication. Translation Quality Assessment offers translators a new set of flexible and modular standards.