Necessary Information for Evaluating Research Conclusions

In a recent study, researchers found that children who engage in regular physical activity display better academic performance compared to their less active peers. The researchers concluded that increased physical activity directly enhances cognitive abilities in children, leading to improved scholastic achievements.

However, some critics argue that the study fails to consider other variables that might influence academic performance, such as socioeconomic status, parental involvement, and access to educational resources. These critics suggest that without controlling for these factors, the relationship between physical activity and academic achievement remains ambiguous.

The researchers rebut by stating that there was a statistically significant correlation observed across different demographics within the study sample, suggesting that increased physical activity remains a key predictor of academic performance, regardless of external factors.

Based on this dialogue, which of the following pieces of information would be necessary to fully assess the validity of the researchers' conclusion?