IDAT Evaluation and Results 3 — Questions and Answers
Question 1: Which statistical measure on an IDAT results report indicates the spread of scores across the test population?
- Standard deviation (Correct answer)
- Mean raw score
- Median percentile
- Mode stanine
Correct answer: Standard deviation
Standard deviation quantifies how much individual scores vary around the mean, reflecting the spread of the score distribution.
Question 2: An institution uses IDAT results to place students into remedial, standard, or advanced courses. This is an example of which use of assessment data?
- Placement decision-making (Correct answer)
- Summative program evaluation
- Formative feedback to teachers
- Certification and licensure
Correct answer: Placement decision-making
Using test results to assign students to course levels is a classic placement function of admissions diagnostic assessments.
Question 3: On the IDAT, what does a scaled score allow that a raw score alone does not?
- Comparison of scores across different test forms (Correct answer)
- Identification of which specific questions were answered incorrectly
- Calculation of the student's IQ
- Determination of time spent per question
Correct answer: Comparison of scores across different test forms
Scaled scores are equated across test forms so that a score of, say, 650 means the same level of ability regardless of which form was administered.
Question 4: A counselor notices a student's IDAT verbal score is significantly lower than their quantitative score. What is the most educationally sound next step?
- Investigate whether the student has a language-based learning need or limited English proficiency (Correct answer)
- Discard the verbal score as an outlier
- Average the two subscores and use only the composite
- Recommend the student retake the entire exam immediately
Correct answer: Investigate whether the student has a language-based learning need or limited English proficiency
A large discrepancy between subscores may signal a specific learning need or language barrier that warrants further investigation.
Question 5: Which of the following BEST explains why IDAT scores are reported as percentile ranks rather than just raw scores?
- Percentile ranks communicate performance relative to other test-takers in a more interpretable way (Correct answer)
- Raw scores are kept confidential by the testing organization
- Percentile ranks are always higher than raw scores
- Raw scores cannot be calculated from standardized tests
Correct answer: Percentile ranks communicate performance relative to other test-takers in a more interpretable way
Percentile ranks give meaning to a score by showing where it falls in the distribution of all test-takers, making comparison straightforward.
Question 6: A school reports that its average IDAT score increased by 8 points this year. Which additional piece of information is needed to judge whether this is educationally meaningful?
- The standard error of measurement for the test (Correct answer)
- The number of test administrators involved
- The color scheme used in the score reports
- Whether the exam was paper-based or digital
Correct answer: The standard error of measurement for the test
Without knowing the SEM, it is impossible to determine whether an 8-point gain exceeds the margin of measurement error and reflects a true change.
Question 7: What is the primary purpose of reporting IDAT results disaggregated by demographic subgroup?
- To identify achievement gaps and inform equity-focused interventions (Correct answer)
- To rank schools by the ethnicity of their student body
- To reduce the number of students who qualify for support services
- To comply with advertising regulations for the testing company
Correct answer: To identify achievement gaps and inform equity-focused interventions
Disaggregated data reveal whether certain groups are being underserved, guiding targeted programs to close achievement gaps.
IDAT Evaluation and Results 3
Which statistical measure on an IDAT results report indicates the spread of scores across the test population?