How many standard deviations must there be between a student's IQ and achievement scores to classify a learning disability?

To classify a learning disability, there typically needs to be a significant discrepancy between a student's IQ score and their achievement scores, generally defined as two standard deviations. In this context, a difference of two standard deviations indicates a stark contrast between cognitive ability as measured by IQ and academic performance in specific areas.

This two-standard-deviation criterion helps to identify students who may have a learning disability because it suggests that despite having average or above-average cognitive potential, their academic performance is markedly lower than expected. This discrepancy is often used in educational assessments to determine eligibility for special education services, providing a clear framework for identifying and supporting students who may benefit from targeted interventions.

Having less than two standard deviations could suggest that the difference is not significant enough to warrant a classification of learning disability, while greater than two standard deviations would reflect an even stronger discrepancy but is not commonly used as the primary threshold for classification. This framework ensures that the educational needs of students who genuinely struggle despite adequate cognitive abilities are appropriately recognized and addressed.