To evaluate the implications of deliberate practice when teaching test administration skills, novice, but trained, graduate student examiners administered intelligence tests to a convenience sample of volunteer school-age examinees assigned to a first test session. A second, different convenience sample of volunteer school-age examinees were administered a final test session by the same graduate student examiners who had acquired more experience and deliberate test administration practice. IQs obtained by examinees in the final test session, when tested by the more experienced examiners, were significantly higher than IQs obtained by examinees in the first test session when tested by novice examiners. These findings highlight the importance of deliberate practice when teaching and learning testing skills. In addition, the findings are consistent with cognitive load theory and have implications for educational data-based decision-making.