Table 2 Cognitive traits analyzed in the present study

Wread

Reading single real words of varied difficulty

Timed word reading in AGS, Finland, France, Hungary, and the Netherlands; Untimed word reading in UK; composite score of timed word reading and reading accuracy in Colorado

Wspell

Spelling single real words after dictation

Spelling accuracy

NWRead

Reading aloud nonsense words of varied difficulty

Timed nonword reading in AGS, Finland, France, Hungary, and the Netherlands; untimed nonword reading in UK and Colorado

PA

Deletion, substitution or swapping of specific phonemes in one or multiple words

Phoneme deletion in AGS, Finland, France, Hungary, and the Netherlands; Phoneme deletion/substitution and spoonerism in UK; composite of phoneme deletion and phoneme segmentation and transposition tasks in Colorado

DigSpan

Reciting a sequence of digits presented by recalling them in the same (forward) and/or reverse (backward) order

WISC (Wechsler intelligence scale for children) forward and backward digit span task

RANdig

Naming as quickly and as accurately as possible a matrix of digits visually presented

Naming speed task (number of digits correctly named per minute)

RANlet

Naming as quickly and as accurately as possible a matrix of letters visually presented

Naming speed task (number of letters correctly named per minute)

RANpic

Naming as quickly and as accurately as possible a matrix of objects visually presented

Naming speed task (number of objects/pictures correctly named per minute)