Subsequently,  found correlations between results in MDS spaces and standard mean opinion score (MOS) tests, but as the MOS tests did not correspond to single dimensions in the MDS space, they suggested that it may be possible to design more informative evaluations by asking subjects to specifically rate each factor of interest (e.g., prosody), where each factor relates to one dimension in the MDS space.
as no specific method is suggested to guarantee reliable prosodic judgments from naive listeners, we have left this question for future research, opting instead to augment the listener ratings gathered in our perception experiment with an expert prosody evaluation and an f0 analysis of the theme phrases.