Assessing translated works has a very long history and the e book by Juliane House (2015) can provide you with a number of insightful models by which you can classify and assess translation errors. To identify and classify errors, however, you should initially perform a textual analysis. Naturally, you need to use a relevant model as tertium comparationis to analyze the source text and to see how the targeted translator has been able to capture the structural and meaning expressions of the source text. Of course, the overall approach you adopt is also very important. In other words, adopting a source based rather than a target based perspectivization may influence your classification of errors. Good luck with your research.