Test for Identification of Signs of Dyslexia: Convergent Validity

Abstract

The aim of this study was to identify support for convergent validity for the Test for Identification of Signs of Dyslexia (TISD). This validity is part of a great field named “evidence of validity based on relations with external criteria”. The support of validity studies for the TISD is still ongoing, and this research is a part of them. The total sample (N = 421) was composed of two groups: sample 1 (n = 371), aged between 6 and 16 years (M = 10.10, SD = 2.33); sample 2 (n = 50), aged between 6 and 10 years (M = 7.94, SD = 0.73). Participants in the two samples were evaluated using TISD and two different test protocols. Convergent validity of the TISD was investigated by comparing subtests of the TISD with already validated instruments, which are assumed to measure the same cognitive abilities, through the Pearson’s correlation and simple linear regression analysis. Pearson’s correlations obtained in the samples showed values between 0.22 (with small effect size, r2 = 0.04) and 0.71 (with large effect size, r2 = 0.50). Linear regression analysis revealed predictions of the TISD regarding the other instruments explaining between 8 and 51% of variance in these measures (with effect sizes between medium and large). These analyses corroborate the convergent validity of the TISD. Considering the prediction of its subtests regarding performance in the domains investigated, the TISD can comprise an important screening tool in the Brazilian context.