Underachievement A discrepancy between a child’s ability and their actual educational achievement. The child’s actual achievement, as reflected in tests and examination results, does not reflect their actual ability and potential. The child fails to achieve their potential due to factors other than ability. These other factors might be internal or external to the child, for example emotional problems or inadequate teaching. With reference to different types of specific learning disabilities the discrepancy is between measured ability (usually by an IQ test) and achievement in terms of reading, writing, spelling and mathematics.