The above-listed publications cite the raw value and z-value improvements of the study participants, which is common for international publications. At schools however, progress is also often measured using percentile ranks and improvements in percentile ranks, which compare students' results on standardized tests against the average score for students in the group. These gains are summarized here for the studies of the publications above.
The largest improvement in percentile ranks was generally achieved for subtraction with large effect sizes. Children with math difficulties were able to improve by as much as 16 points after only 6 weeks of training. The percentile ranks also show large improvements for children without difficulties in math to begin with.