For example, in our earlier human evaluation of HTER, it would have been possible to allocate resources to assessment of the fluency of translations, in addition to adequacy, but this would have come at the cost of reducing the size of the test set by approximately one half.
 Figure 2: Significance test results (Williams test) of statistical significance of a difference in dependent correlations with human assessment for competing out-of-English human-targeted metrics; a green cell denotes a significant increase in correlation with human assessment for the metric in a given row over the metric in a given column at p < 0.05. the decision to include fluency should be weighed against the degree to which reference bias is actually present in the adequacy evaluation.