Question

Translation quality is evaluated using both automatic

metrics and human evaluation, also using the MQM error typology. While

as expected NMT outperforms PB-SMT in terms of committing fewer inflectional

morphology and word-order errors, the authors find that, contrary to previous

results, NMT is better across all language pairs on both short and long sentences

as regards fluency, while the results are less clear when it comes to adequacy

نکته : 

MQM  :  multidimensional quality metrics

NMT : neural machin translation

PB-SMT  : phrase-based statistical machin translation