What are the CAT-5D-QOL & PAT-5D-QOL adaptive questionnaires?
The CAT-5D-QOL is an adaptive (dynamic), generic measure of health-related quality of life (HRQOL). It provides scores for 5 domains of HRQOL (Walking, Handling Objects, Daily Activities, Pain or Discomfort, and Feelings) and an overall, multi-attribute health utility (MAHU) score (dead=0 and perfect health=1; negatives allowed) derived from a standard-gamble experiment. Domain-specific scores are presented either as a percentage of maximum score (0-100) or a difference from the population mean in standard deviation units (mean=50 and SD=10). The adaptive nature of the CAT-5D-QOL means that different respondents answer different questions, depending on their level of HRQOL. A computer selects the questions dynamically from a large pool of questions (item bank), depending on the previous responses. For each domain, the item bank has been calibrated using the methods of item response theory (IRT). As a result, even though different respondents answer different questions, the IRT-based scores are perfectly comparable.
The main advantage of CAT over conventional questionnaires is the ability to achieve the same (or greater) accuracy, precision and responsiveness with fewer questions. In fact, highly accurate scores, with little or no ceiling/floor effect, can be obtained with 5 questions per domain. The CAT-5D-QOL is usually self-administered via the Internet, but can also be administered by an interviewer with Internet access, either by phone or in person. The instrument has been thoroughly validated and used in several research projects.
The PAT-5D-QOL is a “semi-adaptive”, paper-and-pencil measure of HRQOL. It uses items from the CAT-5D-QOL item banks and measures the same 5 domains. For each domain, respondents are initially classified into 4 functional levels. Depending on the level, they respond to a different set of 5 questions. IRT-based scores for each domain and overall health utility (MAHU) scores are provided. The instrument has been validated empirically and tested against CAT-5D-QOL and a “fixed” IRT-based instrument in a simulation study. Measurement properties of the PAT-5D-QOL are intermediate between a fixed questionnaire and a CAT-based questionnaire of the same length.
An advantage of the PAT-5D-QOL is that it does not require a computer for questionnaire administration or special IRT software for scoring. Domain-specific and MAHU scores are obtained using a simple spreadsheet that is provided with the questionnaire. While the PAT-5D-QOL is designed to be administered as a paper-and-pencil questionnaire, it can also be administered on a computer using simple skip logic available in most online survey systems.
How can I access the CAT-5D-QOL & PAT-5D-QOL adaptive questionnaires?
These instruments are available free through Arthritis Research Canada at least until December 31, 2024 (before which we will likely post further extensions). Note that if you begin a research project under a free license, we will provide extensions free of charge through the duration of that project, regardless of any stated expiry dates. Please see below for specific access links.
Computerized Adaptive Test in 5 Domains of Quality of Life (CAT-5D-QOL)
For online questionnaire administration and scoring, the CAT-5D-QOL requires the use of the online Research Survey System (RSS) hosted on a secure server at Arthritis Research Canada. To obtain free access to CAT-5D-QOL, please email esayre at arthritisresearch.ca.
Paper-and-Pencil Semi-Adaptive Test in 5 Domains of Quality of Life (PAT-5D-QOL)
To download the paper questionnaire administration and scoring package (PAT-5D-QOL v2), please click here.
1. Kopec JA, Sayre EC, Rogers P, Davis AM, Badley EM, Anis AH, Abrahamowicz M, Russell L, Rahman MM, Esdaile JM. Multiattribute health utility scoring for the computerized adaptive measure CAT-5D-QOL was developed and validated. J Clin Epidemiol. 2015;pii: S0895-4356(15)00167-5.
2. Kopec JA, Sayre EC, Davis AM, Badley EM, Abrahamowicz M, Pouchot J, Sherlock L, Esdaile JM. Development of a paper-and-pencil semi-adaptive questionnaire for 5 domains of health-related quality of life (PAT-5D-QOL). Qual Life Res. 2013;22(10):2829-42.
3. Davis EM, Lynd LD, Grubisic M, Kopec JA, Sayre EC, Cibere J, Esdaile J, Marra CA. Responsiveness of health state utility values in knee osteoarthritis. J Rheumatol. 2013;40(12):2075-82.
4. Kopec JA, Badii M, McKenna M, Lima VD, Sayre EC, Dvorak M. Computerized adaptive testing in back pain: Validation of the CAT-5D-QOL. Spine 2008;33(12):1384-90.
5. Kopec JA, Sayre EC, Davis AM, Badley EM, Abrahamowicz M, Sherlock L, Williams JI, Anis A, Esdaile JM. Assessment of health-related quality of life in arthritis: Conceptualization and development of five item banks using item response theory. Health Qual Life Outcomes 2006;4(1):33.
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