The interpretation and communication neuropsychological test scores: Putting an end to the Tower of Babel

In practice, clinical neuropsychology shows considerable variability in the statistical interpretation and communication of psychometric test scores in written reports. There is no consensus on the thresholds used to classify a score as statistically “abnormal,” nor on the terminology employed—some practitioners emphasize the likely cognitive deficit (e.g., “deficit performance”), while others focus on statistical deviation (e.g., “average performance”). To address this issue, a group of neuropsychology experts collaborated to draft a summary document, which was then submitted to a consensus conference. This process allowed an independent jury to formulate a series of recommendations. These recommendations are presented in this document, which first outlines the problem of inconsistency in pkwdractices before addressing the issue of threshold scores. Since the definition of threshold scores is linked to pre-interpretative steps, a decision tree is proposed to guide the selection of statistical methods (e.g., z-scores, percentiles), based on characteristics of the normative sample. Additional precautions regarding the use of thresholds are also discussed. Although verifying the psychometric quality of test instruments and normative sampling is a critical consideration, this topic falls outside the scope of threshold and terminology selection and is therefore not addressed in detail here. Finally, the document proposes a standardized labeling system for test scores to promote greater consistency in how neuropsychologists describe performance levels.