@article {170,
	title = {Measuring global physical health in children with cerebral palsy: Illustration of a multidimensional bi-factor model and computerized adaptive testing},
	journal = {Quality of Life Research},
	volume = {18},
	number = {3},
	year = {2009},
	note = {Haley, Stephen MNi, PengshengDumas, Helene MFragala-Pinkham, Maria AHambleton, Ronald KMontpetit, KathleenBilodeau, NathalieGorton, George EWatson, KyleTucker, Carole AK02 HD045354-01A1/HD/NICHD NIH HHS/United StatesK02 HD45354-01A1/HD/NICHD NIH HHS/United StatesResearch Support, N.I.H., ExtramuralResearch Support, Non-U.S. Gov{\textquoteright}tNetherlandsQuality of life research : an international journal of quality of life aspects of treatment, care and rehabilitationQual Life Res. 2009 Apr;18(3):359-70. Epub 2009 Feb 17.},
	month = {Apr},
	pages = {359-370},
	edition = {2009/02/18},
	abstract = {PURPOSE: The purposes of this study were to apply a bi-factor model for the determination of test dimensionality and a multidimensional CAT using computer simulations of real data for the assessment of a new global physical health measure for children with cerebral palsy (CP). METHODS: Parent respondents of 306 children with cerebral palsy were recruited from four pediatric rehabilitation hospitals and outpatient clinics. We compared confirmatory factor analysis results across four models: (1) one-factor unidimensional; (2) two-factor multidimensional (MIRT); (3) bi-factor MIRT with fixed slopes; and (4) bi-factor MIRT with varied slopes. We tested whether the general and content (fatigue and pain) person score estimates could discriminate across severity and types of CP, and whether score estimates from a simulated CAT were similar to estimates based on the total item bank, and whether they correlated as expected with external measures. RESULTS: Confirmatory factor analysis suggested separate pain and fatigue sub-factors; all 37 items were retained in the analyses. From the bi-factor MIRT model with fixed slopes, the full item bank scores discriminated across levels of severity and types of CP, and compared favorably to external instruments. CAT scores based on 10- and 15-item versions accurately captured the global physical health scores. CONCLUSIONS: The bi-factor MIRT CAT application, especially the 10- and 15-item versions, yielded accurate global physical health scores that discriminated across known severity groups and types of CP, and correlated as expected with concurrent measures. The CATs have potential for collecting complex data on the physical health of children with CP in an efficient manner.},
	keywords = {*Computer Simulation, *Health Status, *Models, Statistical, Adaptation, Psychological, Adolescent, Cerebral Palsy/*physiopathology, Child, Child, Preschool, Factor Analysis, Statistical, Female, Humans, Male, Massachusetts, Pennsylvania, Questionnaires, Young Adult},
	isbn = {0962-9343 (Print)0962-9343 (Linking)},
	author = {Haley, S. M. and Ni, P. and Dumas, H. M. and Fragala-Pinkham, M. A. and Hambleton, R. K. and Montpetit, K. and Bilodeau, N. and Gorton, G. E. and Watson, K. and Tucker, C. A.}
}
@article {174,
	title = {Measurement precision and efficiency of multidimensional computer adaptive testing of physical functioning using the pediatric evaluation of disability inventory},
	journal = {Archives of Physical Medicine and Rehabilitation},
	volume = {87},
	number = {9},
	year = {2006},
	note = {Haley, Stephen MNi, PengshengLudlow, Larry HFragala-Pinkham, Maria AK02 hd45354-01/hd/nichdResearch Support, N.I.H., ExtramuralResearch Support, Non-U.S. Gov{\textquoteright}tUnited StatesArchives of physical medicine and rehabilitationArch Phys Med Rehabil. 2006 Sep;87(9):1223-9.},
	month = {Sep},
	pages = {1223-9},
	edition = {2006/08/29},
	abstract = {OBJECTIVE: To compare the measurement efficiency and precision of a multidimensional computer adaptive testing (M-CAT) application to a unidimensional CAT (U-CAT) comparison using item bank data from 2 of the functional skills scales of the Pediatric Evaluation of Disability Inventory (PEDI). DESIGN: Using existing PEDI mobility and self-care item banks, we compared the stability of item calibrations and model fit between unidimensional and multidimensional Rasch models and compared the efficiency and precision of the U-CAT- and M-CAT-simulated assessments to a random draw of items. SETTING: Pediatric rehabilitation hospital and clinics. PARTICIPANTS: Clinical and normative samples. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Not applicable. RESULTS: The M-CAT had greater levels of precision and efficiency than the separate mobility and self-care U-CAT versions when using a similar number of items for each PEDI subdomain. Equivalent estimation of mobility and self-care scores can be achieved with a 25\% to 40\% item reduction with the M-CAT compared with the U-CAT. CONCLUSIONS: M-CAT applications appear to have both precision and efficiency advantages compared with separate U-CAT assessments when content subdomains have a high correlation. Practitioners may also realize interpretive advantages of reporting test score information for each subdomain when separate clinical inferences are desired.},
	keywords = {*Disability Evaluation, *Pediatrics, Adolescent, Child, Child, Preschool, Computers, Disabled Persons/*classification/rehabilitation, Efficiency, Humans, Infant, Outcome Assessment (Health Care), Psychometrics, Self Care},
	isbn = {0003-9993 (Print)},
	author = {Haley, S. M. and Ni, P. and Ludlow, L. H. and Fragala-Pinkham, M. A.}
}
