Item Response Theory (IRT) is an approach to designing and scoring assessments. Assessment is a critical part of teaching and learning. Teachers need a comprehensive assessment system they can trust, one that provides reliable valid data. Imagine Galileo bridges the gap between research and practice. The Imagine Galileo team conducts ongoing research and uses state-of-the-art statistical methods, such as Item Response Theory (IRT), to provide accurate measures of student ability, growth, and achievement. IRT is an approach to designing and scoring assessments. IRT is used by virtually every major educational test including summative tests and by college and career readiness assessments like ACT and SAT.
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What is Item Response Theory? Item Response Theory (IRT) is an approach to designing and scoring assessments.
Item Response Theory is useful because it enables Educators to measure a student's ability, not just their performance on a specific set of items, as well as accurately measure growth by taking into account the difficulty of the test. IRT evaluates the characteristics of items, such as how difficult the item is, whether it discriminates against students with different abilities and if a student is likely to get it right simply by guessing. This information can then be used to build reliable valid assessments and generate scores that are precise estimates of student ability.
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Why is Item Response Theory useful?
- It enables Educators to measure a student's ability, not just their performance on a specific set of items.
- It enables Educators to accurately measure growth by taking into account the difficulty of the test.
Having IRT technology embedded directly into Imagine Galileo, this comprehensive assessment system supports data-driven decision-making to advance student learning. IRT opens a world of possibilities when it comes to assessment design and scoring. In contrast to other assessment systems, it provides an IRT-based Developmental Level (DL) scale score just like the summative state test. The DL score is the measurement of a student's underlying ability, not just their performance on a specific set of items. The DL score also takes into account the characteristics of the items on a test. For example, a student who scores 60% correct on a difficult test will have a higher DL score than a student who scored 60% on an easy test. Imagine Galileo's DL score is placed on a common scale across tests. So if a student's DL score increases from one test to another, we know the student's ability has increased — which is a true measure of student growth.
The information provided from the DL score informed by IRT helps educators to plan instruction, intervention, and enrichment. It also helps students learn and reach their potential by enabling Imagine Galileo to place students into risk-level groups using their DL scores. This information enables Educators to identify specific standards students have learned, what they're ready to learn next, and what's further down the line. Reports based on Developmental Level (DL) scores are available once an Item Response Theory (IRT) analysis is performed by Imagine Learning.
When you meet students where they are and build on their successes, they're more engaged and motivated to learn. IRT helps Imagine Galileo to empower Educators to personalize learning breakthroughs for learners of all developmental levels.