Rauscher L., et al, 2016, Frontiers in Psychology
The authors of this study instructed one third of the participants to practise with Calcularis and another third to practise with Orthograph (the training control group). The remaining third was used as a waiting control group and did not participate in any training. At the end of the study, the difference (if any) in the improvement of maths skills between the Calcularis and Orthograph training groups would show whether it was possible for improvements to be attributed solely to the use of a computer-based training program that did not train maths-specific skills. The training period was 6-8 weeks consisting of at least 24 20-minute training sessions.
In comparison to both the waiting control group and the training control group, the Calcularis training group made greater progress in number line and subtraction tasks, with moderate to to large effect sizes. While the control groups achieved any hardly improvement in mental subtraction tasks – or, with 1.7% fewer correctly solved problems, were even slightly worse – the Calcularis training group saw, on average, an 18% increase in correctly solved problems. As such, the study was able to show that it is not the use of computer-based training in itself that leads to improvement, but rather domain-specific training.