Timed letter-sound identification
Timed letter-sound identification was implemented into the game and assessed at both T1 and T2. Children heard a phoneme and had to select the corresponding grapheme with a computer mouse on the screen as fast as they could. Simple and complex graphemes were presented one by one with five to ten distractors per trial. We tested 32 different graphemes in 42 trials distributed across four levels, each with a time limit of 1 min. The time limit meant that only the fastest children saw all 42 targets, while slower children were only able to see a fraction of that. Based on results of 270 children, internal consistency was high as indicated by Cronbach 