Assessment, Diagnosis, and Program Planning
Domain 3 tests your ability to select measures, read scores correctly, and convert findings into defensible eligibility decisions and IEP content.
Reading the numbers
Most norm-referenced cognitive and achievement tests use a mean of 100 and standard deviation of 15, so 85 is one SD below the mean (about the 16th percentile). Standard scores are preferable to age- or grade-equivalents, which exaggerate small differences and are not interval data. Always report the confidence interval built from the standard error of measurement; a score of 85 with an SEM of 4 gives a 95% confidence band of roughly 77 to 93.
Assessment types to distinguish
- Norm-referenced: compares to a national sample; strong for eligibility questions.
- Criterion-referenced: compares to a standard of mastery; strong for instructional planning.
- Curriculum-based measurement: brief, repeatable probes that reveal slope of improvement; the backbone of progress monitoring.
- Ecological and observational data: settings, antecedents, and functional behavior assessment.
Eligibility and planning
Eligibility requires three findings: a qualifying disability, an adverse effect on educational performance, and a need for specially designed instruction. Present levels of performance must be data-based, and each annual goal needs a condition, a target behavior, and a measurable criterion. In New York, transition planning begins with the IEP in effect when the student turns 12, including a Level 1 vocational assessment and a career plan.
Worked example
A student earns a standard score of 78 in reading comprehension but 102 in math and 105 in listening comprehension. The reasoning: the deficit is specific rather than global, the confidence band excludes the average range, and classroom data confirm the gap. Eligibility is plausible, but only if the team also documents adverse educational impact and need for specialized instruction.
Traps
Reporting age-equivalents as grade placement; deciding eligibility from one score; forgetting the exclusionary factors (language, attendance, lack of instruction); writing goals with no criterion for mastery.