Strengthening the Argument on Visual Aids in Math Performance

In a recent study, researchers found that students who studied using visual aids scored, on average, 15% higher on a nationwide math exam compared to those who did not use visual aids. The researchers concluded that incorporating visual aids into study practices can significantly improve students' performance in mathematics.

However, some educators argue that other factors, such as prior knowledge and study habits, might also contribute to students’ success. They contend that the difference in scores could be attributed to these variables rather than the use of visual aids alone.

To strengthen the researchers' argument regarding the effectiveness of visual aids, which of the following pieces of information would be most helpful?