Assessing the Clinical Accuracy of the Illinois Early Intervention Eligibility Criteria
Thomas, Sarah A.
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Purpose: To qualify for Early Intervention in Illinois, a child must show a 30% developmental delay based on age-equivalent (AE) scores. Unfortunately, the use of AE scores is not empirically supported for determining intervention eligibility because they do not account for the normal variability of scores found within a typical population. The purpose of this project was to establish the likelihood of eligibility misclassifications using the Illinois criterion based on AE scores. Method: Scoring tables from three Illinois pre-approved tests were digitally converted and analyzed using a code written in Visual Basic for Applications, the macro-programming language in Excel, and Python. This code compared all possible combinations of standard scores, AE scores, raw scores, and chronological ages from birth to 36 months to calculate the likelihood of misclassifications based on the Illinois eligibility criterion. Results: In all three tests, misclassifications were identified. In total, 2,447 combinations of scores were found that could lead to the denial of services to children who exhibit developmental delays and 2,966 combinations that could lead to the inappropriate provision of services to typically developing children. Conclusions: The Illinois eligibility criterion based on AE scores was found to be problematic, as shown by the thousands of combinations of scores that could lead to misclassifications on these three tests alone. Early Intervention eligibility criteria must be modified to reflect the best available evidence and in accordance with the administration and scoring procedures of the testing manuals to ensure that these critical services reach the children who need them.