[Letters to the Editor] Interpreting T Scores and Percentile Equivalents Using the MATRICS...

Ringoes, N.J. To the Editor: In the February 2008 issue of the Journal, Robert S. Kern, Ph.D. et al. (1) presented normative data for the National Institute of Mental Health’s Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery. The authors are to be congratulated for conducting a rigorous study that facilitated co-norming and standardization for MATRICS Consensus Cognitive Battery (MCCB) test scores. The resulting normative-derived T scores are useful metrics for assessing the degree of normality or abnormality of any given test score. However, it should be noted that raw test scores need to follow a symmetrical and asymptotic normal distribution curve. Even for a cognitive test with normal distribution in the general population, normality assumptions may still be... [read full story]