If there is a discrepancy between IQ and achievement scores in a report, what is a recommended approach?

• A. Disregard one of the scores and proceed with the other.
• B. Only rely on the higher score for eligibility decisions.
• C. Describe discrepancies, consider measurement error and cross-battery validity, examine context and language factors, and explain implications for eligibility and supports.
• D. Assume the discrepancy invalidates the entire assessment.

Answer: (C)

When IQ and achievement scores don’t line up, the important idea is to interpret the discrepancy using a careful, data-informed approach rather than picking one score or dismissing the difference. The best practice is to describe the discrepancy and interpret it in light of measurement error and cross-battery validity. Look at the magnitude of the difference in the context of each test’s reliability (consider the standard error of measurement) to judge whether the gap is meaningful. Use a cross-battery or multi-measure approach if available to triangulate strengths and weaknesses across instruments, which helps reduce test-specific bias and provides a more reliable picture of cognitive and academic functioning.

Also consider contextual and language factors that might influence achievement scores—such as language proficiency, dialect differences, cultural experiences, motivation, and instructional opportunities—and how these factors might affect performance on testing. Finally, explain the implications for eligibility and supports: how the findings inform decisions about services, accommodations, and targeted interventions. This comprehensive interpretation respects the data, supports fair decisions, and avoids overreliance on a single score.

Disregarding one score or always relying on the higher score overlooks important information and can lead to biased conclusions. Assuming the discrepancy invalidates the entire assessment oversimplifies the situation and ignores how measurement error and context shape test results.