Differences between PROMIS Measures

Computer Adaptive Tests (CATs) versus Short Forms

• Many domains offer a computer adaptive test (CAT) and one or more short forms. Select that type of measure that fits your needs and resources. Learn more>>
  • CATs
    • Tailored selection of items for each respondent
    • Requires administration technology
    • High measurement precision across a wide range of symptom/function severity
  • Short forms
    • All respondents answer all questions
    • No special administration technology needed
    • Degree of measurement precision varies

Measurement Precision: CAT versus Short Form

In 2019, Segawa and colleagues compared PROMIS CATs with 4-, 6-, and 8-item short forms. Specifically, they evaluated the range of accurate scores, number of items administered, floor (level of the worst symptom/function a measure can quantify), and ceiling (level of the best symptom/function a measure can quantify).

• CATs offer the widest range of accurate scores.
• CATs averaged 4.7 items administered.
• 4-, 6-, and 8-item short forms provide a range of accurate scores that improves with longer measures. Figure 1 in their manuscript provides the specific range for each short form. This can be used to evaluate how well each short form is likely to cover the desired range of scores for a target patient sample.
• Use CATs “(1) when a substantial number of participants with extremely poor health is anticipated; (2) when there is a need to measure very healthy participants accurately;” and (3) “when the administration of small number of items is required” (p. 217).

Differences Between Short Forms

• For some domains, there are short forms of different lengths (e.g., 4, 6, 8 items)
• The number of items in a short form is included in the measure name. For example, PROMIS Short Form v1.0 – Fatigue 4a includes 4 items.
• In general, longer short forms offer more measurement precision than shorter short forms.
• Usually, items in a longer short form include all of the items in a shorter short form. For example, all 4 items in the PROMIS Short Form v1.0 – Fatigue 4a measure are included in PROMIS Short Form v1.0 – Fatigue 6a. All of the items in PROMIS Short Form v1.0 – Fatigue 6a are included in the 8a short form.
• More information about how short form items were selected is included in the PROMIS Measure Differences summaries (see below).

Differences Between Standard, Recommended, and Screen-to-CAT

• For some domains, there are computer adaptive tests that use different stopping rules (standard, recommended, screen-to-CAT).
• Standard CATs administer a minimum number of items and stop when a maximum number of items is administered OR the standard error is below a pre-set threshold. Learn more>>
• “Recommended” CATs are shorter, particularly for health, asymptomatic individuals. Learn more>>
• “Screen-to-CAT” measures administer only 1 or 2 items to healthy individuals (screen). Less healthy individuals then continue to complete the “recommended” CAT. Learn more>>

Pediatric Self-report versus Parent Proxy Report

• Pediatric self-report is the standard for measuring outcomes among children.
• Parents can report on their children when the child is too young, cognitively impaired, or too ill to complete a measure.
• Early Childhood Parent-Report measures are for children ages 1 to 5 years old. Parent Proxy measures are for children ages 5 to 17 years old.
• Self-report and parent proxy report scores are not equivalent.
• Early Childhood Parent-Report and Parent Proxy scores are not equivalent.
• It is optimal to assess both the child and parent as their perspectives may independently relate to healthcare utilization, risk factors, or quality of care.

Early Childhood Parent-Report versus Parent Proxy

• Early Childhood Parent-Report measures are completed by parents for children ages 1 to 5 years old.
• Parent Proxy measures are completed by parents for children ages 5 to 17 years old.
• The Early Childhood Parent-Report measures utilized the Parent Proxy item banks as a starting point for measure development, but include unique items and are scored on a separate metric. Scores from Early Childhood Parent-Report measures cannot be compared to scores from Parent Proxy measures.

Physical Function, Mobility, and Upper Extremity

• For adults there are self-report measures of Physical Function, Mobility, and Upper Extremity.
• The Physical Function item bank is the largest collection of items. All items in Mobility and Upper Extremity measures also exist in the Physical Function item bank.
• Physical Function and Mobility measures are scored on the same metric. Scores can be compared.
• Upper Extremity is scored on its own metric. Using its own metric improved measurement properties for individuals with known or suspected upper extremity limitations.
• In general, the PROMIS Physical Function measures have a wider range of measurement (no problems to severe dysfunction) than Mobility measures.
• For pediatric and parent proxy report measures, no general Physical Function measures exist. Mobility and Upper Extremity measures are scored on different metrics and therefore scores cannot be compared.

PROMIS Short Form Profiles versus CAT Profile

• PROMIS profiles include a fixed set of measures covering a wide range of health domains. For example, the PROMIS-29 Profile is a measure for adults that includes 4-item short forms for physical function, fatigue, pain interference, sleep disturbance, depression, anxiety, and ability to participate in social roles and activities as well as a single pain intensity item.
• Most PROMIS profile measures are constructed of short forms. However, the PROMIS Profile CAT v1.0 – 29 is constructed of computer adaptive tests (CATs).
• The CATs included in the PROMIS Profile CAT v1.0 – 29 are fixed to administer 4 items each. This is shorter than the default stopping rule for other PROMIS CATs which allows a CAT to administer a maximum of 12 items. The PROMIS Profile CAT v1.0 – 29 is thus fixed to administer only 29 items.
• Learn more about the content of PROMIS Profiles for adults, pediatric self-report, and parent proxy report.

Differences within a PROMIS Domain

Descriptions of the differences between measures within a domain (e.g., Physical Function) are available Measure Differences summaries. They include information on how measures vary by:

• Version number (e.g., v1.0, v1.1, v2.0)
• Sub-domain (e.g., Physical Function versus Mobility)
• Short form (e.g., 4a, 6b, 8a)
• Respondent (e.g., pediatric self-report versus parent proxy report)

Last updated on 9/18/2024