1 Department of Psychology, Concordia University, Montréal, Quebec, Canada.
2 CISSS de la Montérégie-Centre, INLB/Institut Nazareth et Louis-Braille, Longueuil, Quebec, Canada.
3 Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany.
4 CRIR/Centre de Réadaptation MAB-Mackay du CIUSSS du Centre-Ouest-de-l'Île-de-Montréal, Montréal, Quebec, Canada.

Dyslexia is a language-based neurobiological and developmental learning disability marked by inaccurate and disfluent word recognition, poor decoding, and difficulty spelling. Individuals can be diagnosed with and experience symptoms of dyslexia throughout their lifespan. Screening tools such as the Dyslexia Adult Checklist allow individuals to self-evaluate common risk factors of dyslexia prior to or in lieu of obtaining costly and timely psychoeducational assessments. Although widely available online, the Dyslexia Adult Checklist has yet to be validated. The purpose of this study was to validate this Checklist in a sample of adults with and without dyslexia using both univariate and multivariate statistical approaches. We hypothesised that the Dyslexia Adult Checklist would accurately distinguish between individuals with a self-reported diagnosis of dyslexia (n = 200) and a control group (n = 200), as measured by total scores on the screening tool. Results from our sample found the Dyslexia Adult Checklist to be valid (Cronbach's a = 0.86), and reliable (sensitivity = 76%-91.5%, specificity = 80%-88%). Compared to the originally proposed cut-off score of 45, given the higher sensitivity rate and negative predictive value, we recommend researchers and clinicians use a cut-off score of 40 to indicate possible mild to severe symptoms of dyslexia when using the Dyslexia Adult Checklist.