Computer Adaptive Tests (CATs)

Computer Adaptive Tests (CATs) 

Computer Adaptive Tests (CATs) are a type of measure in which the questions a person answers are tailored to that person. Each response is used to further refine a person’s score.

Item Banks
All CATs begin from an item bank.

• Item bank = collection of items (questions) all measuring the same thing (e.g., physical function)
• Items are ordered by level of difficulty/severity from low (e.g., I have difficulty getting in and out of bed) to high (I am able to run 5 miles) using Item Response Theory

Tailoring Items to a Respondent

1. The first item administered in a CAT is usually one in the middle of the range of function or symptom severity.
2. After a person provides a response, an estimated score is calculated.
3. The CAT algorithm then selects the best item in the item bank for refining the estimated score.
4. After a person provides a response, the estimated score is recalculated.
5. The CAT continues to administer items until:

• A specified level of measurement precision is reached (e.g., <3.0 on a T-score metric) OR
• A specified maximum number of items was administered (generally 12 for HealthMeasures)

Why use CATs?

• Brief - Usually 4-12 items; can be completed in under a minute
• Precise - Low error
• Tailored content - CATs don’t ask questions that aren’t relevant to the respondent
• Cover a wide range of function or symptoms

Learn more about CATs

• Read about Item Response Theory
• Watch this 5-minute introductory video on What is a CAT?

• For a visual explanation of CAT, please see part 6 of Karon Cook’s video series “Applications of IRT".