Aptitude/Achievement Discrepancy Calculation Software for Help in Making Learning Disabilities Qualification Decisions
Overview
Federal Regulations
Traditionally, special education programs were required by federal regulations to demonstrate that students have a severe discrepancy between aptitude (intelligence) and achievement in order to qualify them for special education services under the specific learning disabilities (SLD) category. With the reauthorization of federal special education laws, the Individuals with Disabilities Education Improvement Act of 2004 (IDEA 2004), qualifying students using a severe discrepancy model became an option. Under new federal regulations accompanying IDEA 2004, school districts can choose to continue using a severe discrepancy model, adopt a new model, for example, response to intervention, or use severe discrepancy in combination with other procedures in making SLD eligibility decisions.
Measuring Severe Discrepancy
How to measure severe discrepancy has been a subject of much debate. Further, much criticism has been leveled at state and district special education programs for adopting technically inadequate procedures for measuring aptitude/achievement discrepancies. To address this issue, the United States Department of Education established the Special Education Programs Work Group on Measurements Issues in the Assessment of Learning Disabilities (Reynolds, C.R. (1984-85). Critical measurement issues in learning disabilities. The Journal of Special Education, 18 (4) 451-476.). This group of measurement experts developed the following formula and recommended it as most appropriate for measuring aptitude/achievement discrepancy.
Estimator
Utah adopted the Special Education Programs Work Group formula in 1989. The formula is lengthy and requires a user to know the reliability of the aptitude and achievement tests being employed as well as the correlation between the two tests. In light of this, the Estimator software program was developed to make it easy for special educators to use the formula. Users enter demographic information on the student tested, the names of the aptitude and achievement tests administered, and the tests scores. The program uses the formula to calculate aptitude/achievement discrepancy and determine if the discrepancy is severe. It then generates three reports, (1) a Summary of Discrepancy Information, summarizing demographic and test data for the student and making statements as to whether the test data indicate a severe discrepancy between aptitude and achievement, (2) an Explanation of Percent Confidence, explaining how the program arrived at the level of confidence it did that the test data indicate a severe discrepancy, and (3) an Estimator Formula Intermediate Values report, a technical report showing the values entered for all terms in the formula as well as values for intermediate steps in the calculation.
LD Test Selection Committee
To support the Estimator program, Utah also established the LD Test Selection Committee. The committee seeks to identify and approve as many technically adequate aptitude and achievement tests as possible so that special educators have as many choices as possible when conducting SLD assessments. However, decisions as to which tests are most appropriate for individual students are left to LEA personnel conducting those assessments. The committee meets monthly to review newly published aptitude and achievement tests and determine their appropriateness for use in qualifying students as SLD. Reliability and test-to-test correlation data for tests approved by the committee are entered into the Estimator program. The program has generally been updated and a new version distributed to school districts about every two years. The most recent disc-based version, Estimator: Version 11.0 was published in 2008.
Improvements
New Fomula
In 1999, with publication of Estimator Version 7.0 modifications were made to the original Special Education Programs Work Group formula. The modified formula retained the basic regression characteristics of its predecessor, but incorporated a one-tailed test (the original formula employed a two-tailed test) and a mathematically more elegant way of correcting for test unreliability. The modified formula is shown below.
Web Access
As noted, Estimator was traditionally updated and users provided with new program disks about every two years. Under this distribution method, users had to wait as much as two years after a test was published before it was included in the Estimator program. Beginning in 2009, internet access to Estimator was established. With this distribution method it became possible to add improvement to the progam, including newly approved tests, shortly after they were approved.
Cooperative Effort
Development of Estimator has been a cooperative effort among:
- Utah State University - Center for Persons with Disabilities
- Utah State Office of Education
- Effective Instructional Materials and Systems
Contact Information
For general questions about SLD qualification and Estimator contact:
Richard D. Baer, Ph.D.
(435) 752-6305
rd_baer@msn.com
For specific information about Estimator or to order contact:
Effective Instructional Materials & Systems / DB Enterprises
(435) 752-6305
rd_baer@msn.com