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>>
- 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 Scoring Manuals. Find PROMIS scoring manuals>>
Pediatric Self-report versus Parent Proxy Report
- Pediatric self-report is the standard for measuring outcomes among children
- Parent-proxy report can be used when the child is too young, cognitively impaired, or too ill to complete a measure.
- Self-report and parent-proxy report 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
- Some HealthMeasures have multiple versions (e.g., v1.0, v1.1, v2.0)
- Generally, it is recommended that you use the most recent version available (highest number)
- A decimal increase (v1.0 to v1.1) usually retains the same item-level parameters as well as instrument reliability and validity
- Whole number increases (e.g., v1.0 to v2.0) are used with more substantial changes
- Scoring manuals include detailed information on version differences including when scores from different versions of a measure can be compared with each other.
- Find PROMIS scoring manuals>>
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.