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(3.14) How does the “discrepancy model” of determining whether a student has a specific learning disability work?

(3.14) How does the “discrepancy model” of determining whether a student has a specific learning disability work?

In deciding whether a student has a severe discrepancy between her intellectual ability and her achievement in oral expression, listening comprehension, written expression, basic reading skills, reading comprehension, mathematical calculation, or mathematical reasoning, a school district must review all relevant material available on the student.  No single score or product of scores or test or procedure shall be used as the only factor in making this decision. 

Standardized tests of ability and achievement are often used.  If a student’s achievement scores are sufficiently below his ability scores, it indicates that the student has the severe discrepancy required for special education eligibility under this model. 

As part of their assessment, the assessor will convert the raw scores from both the academic and cognitive testing to a scale of 100 and then compare them.  If there is between a 20-22 point difference (1.5 standard deviation), this is a strong indication that the student has a learning disability.  The discrepancy must be corroborated by other evaluation information, such as from other tests, scales, instruments, observations, and work samples.  [5 C.C.R. Sec. 3030(b)(10)(B).]

Sometimes standardized tests cannot be used for particular students (such as IQ tests for African-American students).  In that case, the discrepancy between ability and achievement must be measured by some other method.  The alternative method of assessment must be specified in the assessment plan, which a parent must sign before any testing may be conducted.  [5 C.C.R. Sec. 3030(b)(10)(B)(2).]

If standardized tests do not show a severe discrepancy between ability and achievement, an IEP team can still find that a severe discrepancy exists.  The IEP team must prepare a report on the student describing the basic psychological process in which the discrepancy exists, the degree of  discrepancy, and the basis and method used to determine the discrepancy.  The report must include information from tests, from the parent, from the pupil’s teacher, from observations of the student, and from his classroom performance and work samples.  However, limited school experience or poor school attendance cannot be the primary cause of the severe discrepancy.  [5 C.C.R. Sec. 3030(b)(10)(B)(3) & (4).]