Methodological concerns are a major reason behind having to turn down papers offered to Developmental Medicine and Child Neurology. One important cause is inadequate validation of measures used in the work. The validity of a test is one of its most important attributes, whether it is a clinical assessment, laboratory assay, electrophysiological or neuroimaging investigation, or a measurement of function, such as motor or IQ scales. With such a plethora of tests used in both everyday clinical work and research, and with the difficulties involved, it is not surprising that some are incompletely validated.