This paper analyses a randomized experiment on the effect of an individualized, digital practice tool on numeracy skills for 337 seventh grade students. The first part of the experiment shows that offering students the opportunity to practice numeracy digitally at home leads to a substantial and significant increase in numeracy performance growth. The second part reveals that the effectiveness of the tool mainly stems from its individualized nature. With good implementation prospects and relatively low costs, the consequences for economic efficiency are discussed to be potentially large.
JEL-Classification – I21, H75, C93.
Key words – Randomized Field Experiments; Digital Practice Tool; Individualization; Numeracy; Secondary Education.