Wright and colleagues suggest in their letter that the statistical methods used in our meta-analysis1 may have led to the underestimation of potential laterality differences in our patient sample. We agree that the use of the variance term 1/(N−3) is not appropriate for the computation of the significance of Cohen q for measurements (which are highly correlated), and may thus lead to an increased risk of type II errors. Therefore, we have recomputed all values of Cohen q using an updated2 version of the formula originally given by Dunn and Clark.3
Nelson MD, Saykin AJ, Flashman LA, Riordan HJ. Testing for Laterality Differences in Regional Brain Volumes. Arch Gen Psychiatry. 2000;57(5):511. doi:
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