@article {168,
	title = {Activity outcome measurement for postacute care},
	journal = {Medical Care},
	volume = {42},
	number = {1 Suppl},
	year = {2004},
	note = {0025-7079Journal ArticleMulticenter Study},
	pages = {I49-161},
	abstract = {BACKGROUND: Efforts to evaluate the effectiveness of a broad range of postacute care services have been hindered by the lack of conceptually sound and comprehensive measures of outcomes. It is critical to determine a common underlying structure before employing current methods of item equating across outcome instruments for future item banking and computer-adaptive testing applications. OBJECTIVE: To investigate the factor structure, reliability, and scale properties of items underlying the Activity domains of the International Classification of Functioning, Disability and Health (ICF) for use in postacute care outcome measurement. METHODS: We developed a 41-item Activity Measure for Postacute Care (AM-PAC) that assessed an individual{\textquoteright}s execution of discrete daily tasks in his or her own environment across major content domains as defined by the ICF. We evaluated the reliability and discriminant validity of the prototype AM-PAC in 477 individuals in active rehabilitation programs across 4 rehabilitation settings using factor analyses, tests of item scaling, internal consistency reliability analyses, Rasch item response theory modeling, residual component analysis, and modified parallel analysis. RESULTS: Results from an initial exploratory factor analysis produced 3 distinct, interpretable factors that accounted for 72\% of the variance: Applied Cognition (44\%), Personal Care \& Instrumental Activities (19\%), and Physical \& Movement Activities (9\%); these 3 activity factors were verified by a confirmatory factor analysis. Scaling assumptions were met for each factor in the total sample and across diagnostic groups. Internal consistency reliability was high for the total sample (Cronbach alpha = 0.92 to 0.94), and for specific diagnostic groups (Cronbach alpha = 0.90 to 0.95). Rasch scaling, residual factor, differential item functioning, and modified parallel analyses supported the unidimensionality and goodness of fit of each unique activity domain. CONCLUSIONS: This 3-factor model of the AM-PAC can form the conceptual basis for common-item equating and computer-adaptive applications, leading to a comprehensive system of outcome instruments for postacute care settings.},
	keywords = {*Self Efficacy, *Sickness Impact Profile, Activities of Daily Living/*classification/psychology, Adult, Aftercare/*standards/statistics \& numerical data, Aged, Boston, Cognition/physiology, Disability Evaluation, Factor Analysis, Statistical, Female, Human, Male, Middle Aged, Movement/physiology, Outcome Assessment (Health Care)/*methods/statistics \& numerical data, Psychometrics, Questionnaires/standards, Rehabilitation/*standards/statistics \& numerical data, Reproducibility of Results, Sensitivity and Specificity, Support, U.S. Gov{\textquoteright}t, Non-P.H.S., Support, U.S. Gov{\textquoteright}t, P.H.S.},
	author = {Haley, S. M. and Coster, W. J. and Andres, P. L. and Ludlow, L. H. and Ni, P. and Bond, T. L. and Sinclair, S. J. and Jette, A. M.}
}
@article {87,
	title = {Refining the conceptual basis for rehabilitation outcome measurement: personal care and instrumental activities domain},
	journal = {Medical Care},
	volume = {42},
	number = {1 Suppl},
	year = {2004},
	note = {0025-7079Journal Article},
	month = {Jan},
	pages = {I62-172},
	abstract = {BACKGROUND: Rehabilitation outcome measures routinely include content on performance of daily activities; however, the conceptual basis for item selection is rarely specified. These instruments differ significantly in format, number, and specificity of daily activity items and in the measurement dimensions and type of scale used to specify levels of performance. We propose that a requirement for upper limb and hand skills underlies many activities of daily living (ADL) and instrumental activities of daily living (IADL) items in current instruments, and that items selected based on this definition can be placed along a single functional continuum. OBJECTIVE: To examine the dimensional structure and content coverage of a Personal Care and Instrumental Activities item set and to examine the comparability of items from existing instruments and a set of new items as measures of this domain. METHODS: Participants (N = 477) from 3 different disability groups and 4 settings representing the continuum of postacute rehabilitation care were administered the newly developed Activity Measure for Post-Acute Care (AM-PAC), the SF-8, and an additional setting-specific measure: FIM (in-patient rehabilitation); MDS (skilled nursing facility); MDS-PAC (postacute settings); OASIS (home care); or PF-10 (outpatient clinic). Rasch (partial-credit model) analyses were conducted on a set of 62 items covering the Personal Care and Instrumental domain to examine item fit, item functioning, and category difficulty estimates and unidimensionality. RESULTS: After removing 6 misfitting items, the remaining 56 items fit acceptably along the hypothesized continuum. Analyses yielded different difficulty estimates for the maximum score (eg, "Independent performance") for items with comparable content from different instruments. Items showed little differential item functioning across age, diagnosis, or severity groups, and 92\% of the participants fit the model. CONCLUSIONS: ADL and IADL items from existing rehabilitation outcomes instruments that depend on skilled upper limb and hand use can be located along a single continuum, along with the new personal care and instrumental items of the AM-PAC addressing gaps in content. Results support the validity of the proposed definition of the Personal Care and Instrumental Activities dimension of function as a guide for future development of rehabilitation outcome instruments, such as linked, setting-specific short forms and computerized adaptive testing approaches.},
	keywords = {*Self Efficacy, *Sickness Impact Profile, Activities of Daily Living/*classification/psychology, Adult, Aged, Aged, 80 and over, Disability Evaluation, Factor Analysis, Statistical, Female, Humans, Male, Middle Aged, Outcome Assessment (Health Care)/*methods/statistics \& numerical data, Questionnaires/*standards, Recovery of Function/physiology, Rehabilitation/*standards/statistics \& numerical data, Reproducibility of Results, Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S., Research Support, U.S. Gov{\textquoteright}t, P.H.S., Sensitivity and Specificity},
	author = {Coster, W. J. and Haley, S. M. and Andres, P. L. and Ludlow, L. H. and Bond, T. L. and Ni, P. S.}
}
@article {30,
	title = {Calibration of an item pool for assessing the burden of headaches: an application of item response theory to the Headache Impact Test (HIT)},
	journal = {Quality of Life Research},
	volume = {12},
	number = {8},
	year = {2003},
	note = {0962-9343Journal Article},
	pages = {913-933},
	abstract = {BACKGROUND: Measurement of headache impact is important in clinical trials, case detection, and the clinical monitoring of patients. Computerized adaptive testing (CAT) of headache impact has potential advantages over traditional fixed-length tests in terms of precision, relevance, real-time quality control and flexibility. OBJECTIVE: To develop an item pool that can be used for a computerized adaptive test of headache impact. METHODS: We analyzed responses to four well-known tests of headache impact from a population-based sample of recent headache sufferers (n = 1016). We used confirmatory factor analysis for categorical data and analyses based on item response theory (IRT). RESULTS: In factor analyses, we found very high correlations between the factors hypothesized by the original test constructers, both within and between the original questionnaires. These results suggest that a single score of headache impact is sufficient. We established a pool of 47 items which fitted the generalized partial credit IRT model. By simulating a computerized adaptive health test we showed that an adaptive test of only five items had a very high concordance with the score based on all items and that different worst-case item selection scenarios did not lead to bias. CONCLUSION: We have established a headache impact item pool that can be used in CAT of headache impact.},
	keywords = {*Cost of Illness, *Decision Support Techniques, *Sickness Impact Profile, Adolescent, Adult, Aged, Comparative Study, Disability Evaluation, Factor Analysis, Statistical, Headache/*psychology, Health Surveys, Human, Longitudinal Studies, Middle Aged, Migraine/psychology, Models, Psychological, Psychometrics/*methods, Quality of Life/*psychology, Software, Support, Non-U.S. Gov{\textquoteright}t},
	author = {Bjorner, J. B. and Kosinski, M. and Ware, J. E., Jr.}
}
@article {34,
	title = {Developing an initial physical function item bank from existing sources},
	journal = {Journal of Applied Measurement},
	volume = {4},
	number = {2},
	year = {2003},
	note = {1529-7713Journal Article},
	pages = {124-36},
	abstract = {The objective of this article is to illustrate incremental item banking using health-related quality of life data collected from two samples of patients receiving cancer treatment. The kinds of decisions one faces in establishing an item bank for computerized adaptive testing are also illustrated. Pre-calibration procedures include: identifying common items across databases; creating a new database with data from each pool; reverse-scoring "negative" items; identifying rating scales used in items; identifying pivot points in each rating scale; pivot anchoring items at comparable rating scale categories; and identifying items in each instrument that measure the construct of interest. A series of calibrations were conducted in which a small proportion of new items were added to the common core and misfitting items were identified and deleted until an initial item bank has been developed.},
	keywords = {*Databases, *Sickness Impact Profile, Adaptation, Psychological, Data Collection, Humans, Neoplasms/*physiopathology/psychology/therapy, Psychometrics, Quality of Life/*psychology, Research Support, U.S. Gov{\textquoteright}t, P.H.S., United States},
	author = {Bode, R. K. and Cella, D. and Lai, J. S. and Heinemann, A. W.}
}
@article {31,
	title = {The feasibility of applying item response theory to measures of migraine impact: a re-analysis of three clinical studies},
	journal = {Quality of Life Research},
	volume = {12},
	number = {8},
	year = {2003},
	note = {0962-9343Journal Article},
	pages = {887-902},
	abstract = {BACKGROUND: Item response theory (IRT) is a powerful framework for analyzing multiitem scales and is central to the implementation of computerized adaptive testing. OBJECTIVES: To explain the use of IRT to examine measurement properties and to apply IRT to a questionnaire for measuring migraine impact--the Migraine Specific Questionnaire (MSQ). METHODS: Data from three clinical studies that employed the MSQ-version 1 were analyzed by confirmatory factor analysis for categorical data and by IRT modeling. RESULTS: Confirmatory factor analyses showed very high correlations between the factors hypothesized by the original test constructions. Further, high item loadings on one common factor suggest that migraine impact may be adequately assessed by only one score. IRT analyses of the MSQ were feasible and provided several suggestions as to how to improve the items and in particular the response choices. Out of 15 items, 13 showed adequate fit to the IRT model. In general, IRT scores were strongly associated with the scores proposed by the original test developers and with the total item sum score. Analysis of response consistency showed that more than 90\% of the patients answered consistently according to a unidimensional IRT model. For the remaining patients, scores on the dimension of emotional function were less strongly related to the overall IRT scores that mainly reflected role limitations. Such response patterns can be detected easily using response consistency indices. Analysis of test precision across score levels revealed that the MSQ was most precise at one standard deviation worse than the mean impact level for migraine patients that are not in treatment. Thus, gains in test precision can be achieved by developing items aimed at less severe levels of migraine impact. CONCLUSIONS: IRT proved useful for analyzing the MSQ. The approach warrants further testing in a more comprehensive item pool for headache impact that would enable computerized adaptive testing.},
	keywords = {*Sickness Impact Profile, Adolescent, Adult, Aged, Comparative Study, Cost of Illness, Factor Analysis, Statistical, Feasibility Studies, Female, Human, Male, Middle Aged, Migraine/*psychology, Models, Psychological, Psychometrics/instrumentation/*methods, Quality of Life/*psychology, Questionnaires, Support, Non-U.S. Gov{\textquoteright}t},
	author = {Bjorner, J. B. and Kosinski, M. and Ware, J. E., Jr.}
}
@article {48,
	title = {Advances in quality of life measurements in oncology patients},
	journal = {Seminars in Oncology},
	volume = {29},
	number = {3 Suppl 8},
	year = {2002},
	note = {0093-7754 (Print)Journal ArticleReview},
	month = {Jun},
	pages = {60-8},
	abstract = {Accurate assessment of the quality of life (QOL) of patients can provide important clinical information to physicians, especially in the area of oncology. Changes in QOL are important indicators of the impact of a new cytotoxic therapy, can affect a patient{\textquoteright}s willingness to continue treatment, and may aid in defining response in the absence of quantifiable endpoints such as tumor regression. Because QOL is becoming an increasingly important aspect in the management of patients with malignant disease, it is vital that the instruments used to measure QOL are reliable and accurate. Assessment of QOL involves a multidimensional approach that includes physical, functional, social, and emotional well-being, and the most comprehensive instruments measure at least three of these domains. Instruments to measure QOL can be generic (eg, the Nottingham Health Profile), targeted toward specific illnesses (eg, Functional Assessment of Cancer Therapy - Lung), or be a combination of generic and targeted. Two of the most widely used examples of the combination, or hybrid, instruments are the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 Items and the Functional Assessment of Chronic Illness Therapy. A consequence of the increasing international collaboration in clinical trials has been the growing necessity for instruments that are valid across languages and cultures. To assure the continuing reliability and validity of QOL instruments in this regard, item response theory can be applied. Techniques such as item response theory may be used in the future to construct QOL item banks containing large sets of validated questions that represent various levels of QOL domains. As QOL becomes increasingly important in understanding and approaching the overall management of cancer patients, the tools available to clinicians and researchers to assess QOL will continue to evolve. While the instruments currently available provide reliable and valid measurement, further improvements in precision and application are anticipated.},
	keywords = {*Quality of Life, *Sickness Impact Profile, Cross-Cultural Comparison, Culture, Humans, Language, Neoplasms/*physiopathology, Questionnaires},
	author = {Cella, D. and Chang, C-H. and Lai, J. S. and Webster, K.}
}
