In Brazil, there is a lack of valid instruments for screening for Developmental Dyslexia (DD) and so the aim of this study was an in-depth investigation of evidence of validity based on the relations with external variables for the Identifying Signs of Dyslexia Test (TISD). More specifically, it seeks to investigate the validity of the criterion, i.e. whether such instruments would be capable of identifying this diagnosis. The research involved comparing two samples: (a) children with DD diagnosis (n = 15) and (b) children without complaints of reading and writing difficulties (n = 146). It was found that in all the subtests of which the instrument is made up (reading, writing, visual attention, calculation, motor skills, phonological awareness, rapid naming, short term memory) there were significant differences between the groups, and in the test total. The results suggest that the TISD was able to identify the group with DD, evidencing the validity of the criterion for this instrument.
psychometry; learning; neuropsychology; psychological evaluation