Multidimensional computerized adaptive testing of the EORTC QLQ-C30: basic developments and evaluations.
OBJECTIVE
Self-report questionnaires are widely used to measure health-related quality of life (HRQOL). Ideally, such questionnaires should be adapted to the individual patient and at the same time scores should be directly comparable across patients. This may be achieved using computerized adaptive testing (CAT). Usually, CAT is carried out for a single domain at a time. However, many HRQOL domains are highly correlated. Multidimensional CAT may utilize these correlations to improve measurement efficiency. We investigated the possible advantages and difficulties of multidimensional CAT.


METHODS
We evaluated multidimensional CAT of three scales from the EORTC QLQ-C30: the physical functioning, emotional functioning, and fatigue scales. Analyses utilised a database with 2958 European cancer patients.


RESULTS
It was possible to obtain scores for the three domains with five to seven items administered using multidimensional CAT that were very close to the scores obtained using all 12 items and with no or little loss of measurement precision.


CONCLUSIONS
The findings suggest that multidimensional CAT may significantly improve measurement precision and efficiency and encourage further research into multidimensional CAT. Particularly, the estimation of the model underlying the multidimensional CAT and the conceptual aspects need further investigations.
Petersen
Morten Aa
MA
The Research Unit, Department of Palliative Medicine, Bispebjerg Hospital, DK-2400, Copenhagen, NV, Denmark. map01@bbh.hosp.dk
Groenvold
Mogens
M
Aaronson
Neil
N
Fayers
Peter
P
Sprangers
Mirjam
M
Bjorner
Jakob B
JB
D000328:Adult; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012650:Self Disclosure; D011795:Surveys and Questionnaires / Q000592:standards*; D014584:User-Computer Interface