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Differences Between CAT Measures

CAT Variations

What Are CAT Variations?

HealthMeasures includes multiple types of computer adaptive tests (CATs) that vary according to their stopping rules. Stopping rules determine when a CAT stops administering items to a respondent. These rules are selected to maximize measurement precision while reducing respondent burden. This is done through setting rules for how precise the score should be (the standard error) and setting limits on the number of items to administer. Learn more about the measurement science behind CATs.

Types of Stopping Rules

CATs use multiple rules to determine when to stop. These rules include:

  • Minimum number of items to be administered
  • Maximum number of items to be administered
  • Standard error below a specific threshold
  • Standard error change
  • Endorsement of extreme responses to first item(s)

Types of CATs

Recommended CATs include the newest CAT stopping rules, designed to administer less items for healthier, asymptomatic individuals, further reducing respondent burden.

Standard CATs administer items until a maximum count or standard error threshold is reached, ensuring thorough measurement across a domain’s full spectrum with precise scores.

Screen-to-CATs use enhanced stopping rules that administer only 1-2 items to healthy individuals (screen). Less healthy individuals continue past the screening item(s) with the Recommended CAT.

PROMIS® Profile CAT v1.0 – 29 provides the advantages of CATs (appropriate for all uses, brief, precise) with only 29 items across 7 domains. This measure includes 7 CATs, fixed to administer exactly 4 items per CAT, and a pain intensity rating item.

Learn more about which CAT to administer.

Stopping Rules for HealthMeasures CATs

  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 12 items are administered1 OR
    • The standard error is below a threshold (0.3 on the theta metric or 3.0 on the T-score metric)

1The following Adult CATs administer a maximum number of 10 items:

    • PROMIS Item Bank v2.0 – Pain Behavior
    • PROMIS Bank v1.0 – General Life Satisfaction
    • PROMIS Bank v1.0 – General Self-Efficacy
  • Minimum number of items administered = 4
  • Stop when one of these occurs:
      • 8 items are administered OR
      • The standard error is below 0.3 on the theta metric (3.0 on the T-score metric) OR
      • The standard error changes by less than 0.01 on the theta metric (0.1 on the T-score metric)
  • If the response to the first item is the “healthiest” response, then stop.
  • If the response to the first item is NOT the “healthiest” response, proceed with the Recommended CAT stopping rules.
  • Minimum number of items administered2 = 5
  • Stop when one of these occurs:
    • 12 items are administered OR
    • The standard error is below a threshold (0.4 on the theta metric or 4.0 on the T-score metric)

2The following Pediatric and Parent Proxy CATs administer a minimum number of 4 items:

  • PROMIS Pediatric Bank v1.0 – Family Relationships
  • PROMIS Parent Proxy Bank v1.0 – Family Relationships
  • PROMIS Parent Proxy Bank v1.0 – Cognitive Function (also uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Parent Proxy Bank v1.0 – Stigma (also stops when 8 items are administered and uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Parent Proxy Bank v1.0 – Stigma – Skin (also stops when 8 items are administered and uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Parent Proxy Bank v1.1 – Cognitive Function (also uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Pediatric Bank v1.1 – Stigma (also stops when 8 items are administered and uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Pediatric Bank v1.1 – Stigma – Skin (also stops when 8 items are administered and uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Pediatric Bank v2.0 – Pain Quality (also uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Pediatric Bank v1.0 – Sleep-Related Impairment (also uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Parent Proxy Bank v1.0 – Sleep-Related Impairment (also uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Parent Proxy Bank v1.0 – Sleep Disturbance (also uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • PROMIS Pediatric Bank v1.0 – Sleep Disturbance (also uses standard error < 0.3 on the theta metric or 3.0 on the T-score metric)
  • Minimum number of items administered = 5
  • Stop when one of these occurs:
    • 12 items are administered OR
    • The standard error is below a threshold (0.4 on the theta metric or 4.0 on the T-score metric) OR
    • The standard error changes by less than 0.01 on the theta metric (0.1 on the T-score metric)
  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 8 items are administered OR
    • The standard error is below a threshold (0.3 on the theta metric or 3.0 on the T-score metric) OR
    • The standard error changes by less than 0.01 on the theta metric (0.1 on the T-score metric)
  • If the responses to the first two items are both the “healthiest” responses, then stop.
  • If the responses to the first two items are both NOT the “healthiest” responses, proceed with the Recommended CAT stopping rules.
  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 8 items are administered OR
    • The standard error is below a threshold (0.4 on the theta metric or 4.0 on the T-score metric)
  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 12 items are administered OR
    • The standard error is below a threshold (0.3 on the theta metric or 3.0 on the T-score metric)

3The Neuro-QoL Pediatric Bank v1.0 – Stigma CAT administers a maximum of 8 items.

The Neuro-QoL Pediatric Bank v2.1 – Fatigue CAT administers a maximum of 11 items.

Adult v3.0

  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 8 items are administered OR
    • The standard error is below 0.224 (theta metric)

Adult v2.04

  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 12 items are administered OR
    • The standard error is below 0.3 (theta metric)

4The NIH Toolbox Sadness CAT Age 18+ v2.0 administers a maximum of 8 items and stops when the standard error changes by less than 0.01 on the theta metric (0.1 on the T-score metric).

The following Adult CAT administers a maximum number of 10 items:

  • NIH Toolbox General Life Satisfaction CAT Age 18+ v2.0
  • NIH Toolbox Self-Efficacy CAT Age 18+ v2.0

Pediatric (Ages 8-17) v3.05

  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 8 items are administered OR
    • The standard error is below 0.3 (theta metric)

5The NIH Toolbox Emotional Support CAT Ages 8-17 v3.0 administers a maximum of 7 items.

The NIH Toolbox Friendship CAT Ages 8-17 v3.0 administers a maximum of 5 items.

Pediatric (Ages 8-17) v2.0

  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 10 items are administered OR
    • The standard error is below 0.3 (theta metric)

Parent Report (Ages 3-7 and Ages 8-12) v3.06

  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 8 items are administered OR
    • The standard error is below 0.3 (theta metric

6The NIH Toolbox Sadness/Depression Parent Report CAT Ages 8-12 v3.0 stops when the standard error is below 0.224 (theta metric).

The NIH Toolbox Sadness/Depression Parent Report CAT Ages 3-7 v3.0 administers a maximum of 7 items or stops when the standard error is below 0.224 (theta metric).

Parent-Report (Ages 3-7 and Ages 8-12) v2.07

  • Minimum number of items administered = 4
  • Stop when one of these occurs:
    • 10 items are administered OR
    • The standard error is below 0.3 (theta metric)

7The NIH Toolbox Sadness Parent Report CAT Ages 8-12 v2.0 administers a maximum of 11 items and stops when the standard error changes by less than 0.01 on the theta metric (0.1 on the T-score metric).

The following Parent Report CAT administers a maximum number of 12 items:

  • NIH Toolbox Positive Affect Parent Report CAT Ages 3-7 v2.0
  • NIH Toolbox Positive Affect Parent Report CAT Ages 8-12 v2.0

Emotional Impact:

  • Minimum number of items administered = 3
  • Stop when one of these occurs:
    • 20 items are administered OR
    • The standard error is below a threshold (0.2 on the theta metric or 2.0 on the T-score metric)

Pain Impact:

  • Minimum number of items administered = 3
  • Stop when one of these occurs:
    • 13 items are administered OR
    • The standard error is below a threshold (0.2 on the theta metric or 2.0 on the T-score metric)

Sleep Impact:

  • Minimum number of items administered = 3
  • Stop when one of these occurs:
    • 12 items are administered OR
    • The standard error is below a threshold (0.2 on the theta metric or 2.0 on the T-score metric)

Social Functioning Impact:

  • Minimum number of items administered = 3
  • Stop when one of these occurs:
    • 17 items are administered OR
    • The standard error is below a threshold (0.2 on the theta metric or 2.0 on the T-score metric)

Stiffness Impact:

  • Minimum number of items administered = 3
  • Stop when one of these occurs:
    • 15 items are administered ORThe standard error is below a threshold (0.2 on the theta metric or 2.0 on the T-score metric)

Last updated: September 29, 2026