I was interested to read the article by Brunetto and colleagues published in the September 2014 edition of the Journal . The purpose of the authors was to correlate the amount of jaw displacement with the volume variation and the minimal cross-sectional area of the pharyngeal airway.

I found the title to be incorrect because, for prediction purposes, using the Pearson correlation test is a common mistake. Moreover, for prediction studies, we need 2 different cohort data sets or at least a split cohort data set to develop our prediction model and then validate it. So, appropriate study design as well as validating our model should be considered in prediction studies.

Brunetto et al concluded that only the maxillary displacement is a reliable predictor of the minimal cross-sectional area variation after maxillomandibular advancement. Such a conclusion may lead to a misleading message and mismanagement of the patients.