2.2. Psychometric measures

Psychometric assessment was conducted at two distinct developmental time points: before literacy acquisition at the end of the last year of kindergarten (T1) and at the end of the second grade of primary school (T2).

At preliterate age (T1), children were tested for non‐verbal intelligence and cognitive–linguistic skills associated with literacy. Non‐verbal intelligence was tested with Raven's Colored Progressive Matrices (CPM; Raven, Court, & Raven, 1998). PA, RAN, phonological short‐term memory, and visual attention control were assessed using the standardized screening Bielefelder Screening zur Früherkennung von Lese‐Rechtschreibschwierigkeiten (BISC; Jansen, 2002). An age‐normed risk score for the development of dyslexia was calculated for each child based on all subtests of the BISC.

At T2 (i.e., after two years of formal reading instruction), children completed a battery of standardized reading and spelling tests along with further psychometric assessments. Non‐verbal intelligence was retested with the Wechsler Intelligence Scale for Children (WISC‐IV; Petermann & Petermann, 2014). We added measures of verbal development (scope of lexicon) and non‐verbal working memory (digit span) also using the WISC‐IV. To characterize literacy development, speed and accuracy of single word and pseudoword reading were tested (two subtests of the Lese‐ und Rechtschreibtest II—Weiterentwicklung des Salzbuger Lese‐ und Rechtschreibtest; SLRT‐II; Moll & Landerl, 2010). Reading speed and comprehension on the sentence level were evaluated using a plausibility judgment test (Salzburger Lese‐Screening für die Klassenstufen 1–4; SLS; Mayringer & Wimmer, 2008). The age‐normed SLS score is a combined score capturing reading speed and accuracy with a scaling that is equal to the intelligence quotient. Furthermore, reading comprehension was tested on three levels of increasing complexity, from word meaning to text comprehension (ELFE 1–6: Ein Lesesinnverständnistest für Erst‐ bis Sechstklässler; Lenhard & Schneider, 2006). Finally, writing and spelling skills were assessed using a short spelling task (DERET 1–2+: Deutscher Rechschreibtest für das erste und zweite Schuljahr; Stock & Schneider, 2008). Psychometric assessment was completed by testing PA (Basiskompetenzen für Lese‐Rechtschreibleistungen: BAKO 1–4; Ein Test zur Erfassung der Phonologischen Bewusstheit vom ersten bis vierten Grundschuljahr; Stock, Marx, Schneider, & Schneider, 2003; subtests: phoneme transition, sound categorization, vocal length) and children's exposure to books (K‐TRT: Kinder Titelrekognitionstest; Schroeder, Segbers, & Schröter, 2016). Finally, handedness was assessed as the hand with which children wrote.