Differentiating Among Gifted Learners: A Comparison of Classical Test Theory and Item Response Theory on Above-Level Testing
Brandon LeBeau, Susan G. Assouline, Duhita Mahatmya, Ann Lupkowski-Shoplik
Belin-Blank Center, University of Iowa Above Level Testing
Participate in a Talent Search (for example, a university-based talent search)
Above-level testing in school using available instruments or through a university program. For example, www.i-excel.org
Above-level testing helps us discover talented students and tailor educational options for them
BESTS In School Testing
Belin-Blank Exceptional Student Talent Search (BESTS)
4th – 6th graders: Take I-Excel in school , not on the traditional open Saturday testing offered throughout the U.S.
The goal: More students have access to above-level testing
Available to any talented student in the school
Not just for those whose parents show initiative to register for testing
A new, online test, I-Excel…
…is an online test for very capable 4th – 6th graders
uses an online platform developed by the Belin-Blank Center for use as an above-level assessment
…licenses content developed by ACT
that was designed to measure academic progress of junior high students.
From that content, Belin-Blank has been identifying the academic talents of bright 4th- 6th grade students for over 20 years.
…provides the power of above-level testing
I-Excel
Science (28 items)
Math (30 items)
Reading (30 items)
English (40 items)
Contains 8th grade level items
Used as an above-level test for 4th-6th graders
Challenges for use
Reliability and validity are for an 8th grade normative sample
Is not a high-achieving sample
Would like the score to represent aptitude
Same score range for all students
Ignores grade student currently is in
Ignores how far away student is from 8th grade content exposure
Research Questions
To what extent does the information obtained through CTT compare with information obtained from IRT in the above-level testing environment?
How does the item level analysis with IRT impact aptitude estimates?
To what extent do CTT and IRT methods provide similar classifications of high-aptitude for students initially identified as high-achieving?
Who this research benefits
Researchers
Practioners, teachers, parents could use the IRT aptitude scores
Sample
1,893 students took I-Excel between March 2016 through July 2017
Grades:
4th: 13.7%
5th: 28.1%
6th: 58.2%
Sex:
Students took all four subareas (English, Math, Reading, and Science)
Classical Test Theory (CTT)
Number of questions answers correctly
Percentile Ranks
Item-level statistics
Proportion correct
Biserial correlations
Statistics are sample dependent
Scores based on 8th grade normative sample
Item Response Theory (IRT)
Mathematical model
Similar to logistic regression, but with a latent variable (i.e. aptitude)
Individual response strings are used to estimate...
item parameters (i.e. discrimination, difficulty)
person parameters (i.e. aptitude)
Accounted for grade through multigroup IRT framework
IRT Uses Student Response Strings
Additional IRT Benefits
Create developmental scale
Could move to computer adaptive testing
Can use IRT linking methods
CTT Violin Plots
Differentiating students
Average Aptitude Estimates
Identify students ready for additional challenge
Enhancing the 4Ds of talent development through IRT scale
Improve reliability and validity of estimates of high-achieving students' aptitude
Broaden identification of high-achieving students ready for advanced curriculum
Better align assessments to interventions (e.g., enrichment, acceleration)
Refine evaluation of high-achieving students' growth in domains
Proportion Correct
Explore Aptitude for Identification
Resume presentation
Differentiating Among Gifted Learners: A Comparison of Classical Test Theory and Item Response Theory on Above-Level Testing
Brandon LeBeau, Susan G. Assouline, Duhita Mahatmya, Ann Lupkowski-Shoplik
Belin-Blank Center, University of Iowa