@article {237,
	title = {Factor analysis techniques for assessing sufficient unidimensionality of cancer related fatigue},
	journal = {Quality of Life Research},
	volume = {15},
	number = {7},
	year = {2006},
	note = {0962-9343 (Print)Journal ArticleResearch Support, N.I.H., Extramural},
	month = {Sep},
	pages = {1179-90},
	abstract = {BACKGROUND: Fatigue is the most common unrelieved symptom experienced by people with cancer. The purpose of this study was to examine whether cancer-related fatigue (CRF) can be summarized using a single score, that is, whether CRF is sufficiently unidimensional for measurement approaches that require or assume unidimensionality. We evaluated this question using factor analysis techniques including the theory-driven bi-factor model. METHODS: Five hundred and fifty five cancer patients from the Chicago metropolitan area completed a 72-item fatigue item bank, covering a range of fatigue-related concerns including intensity, frequency and interference with physical, mental, and social activities. Dimensionality was assessed using exploratory and confirmatory factor analysis (CFA) techniques. RESULTS: Exploratory factor analysis (EFA) techniques identified from 1 to 17 factors. The bi-factor model suggested that CRF was sufficiently unidimensional. CONCLUSIONS: CRF can be considered sufficiently unidimensional for applications that require unidimensionality. One such application, item response theory (IRT), will facilitate the development of short-form and computer-adaptive testing. This may further enable practical and accurate clinical assessment of CRF.},
	keywords = {*Factor Analysis, Statistical, *Quality of Life, Aged, Chicago, Fatigue/*etiology, Female, Humans, Male, Middle Aged, Neoplasms/*complications, Questionnaires},
	author = {Lai, J-S. and Crane, P. K. and Cella, D.}
}
@article {236,
	title = {An item bank was created to improve the measurement of cancer-related fatigue},
	journal = {Journal of Clinical Epidemiology},
	volume = {58},
	number = {2},
	year = {2005},
	note = {Lai, Jin-SheiCella, DavidDineen, KellyBode, RitaVon Roenn, JamieGershon, Richard CShevrin, DanielEnglandJ Clin Epidemiol. 2005 Feb;58(2):190-7.},
	month = {Feb},
	pages = {190-7},
	type = {Multicenter Study},
	edition = {2005/02/01},
	abstract = {OBJECTIVE: Cancer-related fatigue (CRF) is one of the most common unrelieved symptoms experienced by patients. CRF is underrecognized and undertreated due to a lack of clinically sensitive instruments that integrate easily into clinics. Modern computerized adaptive testing (CAT) can overcome these obstacles by enabling precise assessment of fatigue without requiring the administration of a large number of questions. A working item bank is essential for development of a CAT platform. The present report describes the building of an operational item bank for use in clinical settings with the ultimate goal of improving CRF identification and treatment. STUDY DESIGN AND SETTING: The sample included 301 cancer patients. Psychometric properties of items were examined by using Rasch analysis, an Item Response Theory (IRT) model. RESULTS AND CONCLUSION: The final bank includes 72 items. These 72 unidimensional items explained 57.5\% of the variance, based on factor analysis results. Excellent internal consistency (alpha=0.99) and acceptable item-total correlation were found (range: 0.51-0.85). The 72 items covered a reasonable range of the fatigue continuum. No significant ceiling effects, floor effects, or gaps were found. A sample short form was created for demonstration purposes. The resulting bank is amenable to the development of a CAT platform.},
	keywords = {Adult, Aged, Aged, 80 and over, Factor Analysis, Statistical, Fatigue/*etiology/psychology, Female, Humans, Male, Middle Aged, Neoplasms/*complications/psychology, Psychometrics, Questionnaires},
	isbn = {0895-4356 (Print)0895-4356 (Linking)},
	author = {Lai, J-S. and Cella, D. and Dineen, K. and Bode, R. and Von Roenn, J. and Gershon, R. C. and Shevrin, D.}
}
@article {238,
	title = {Item banking to improve, shorten and computerized self-reported fatigue: an illustration of steps to create a core item bank from the FACIT-Fatigue Scale},
	journal = {Quality of Life Research},
	volume = {12},
	number = {5},
	year = {2003},
	note = {0962-9343Journal Article},
	month = {Aug},
	pages = {485-501},
	abstract = {Fatigue is a common symptom among cancer patients and the general population. Due to its subjective nature, fatigue has been difficult to effectively and efficiently assess. Modern computerized adaptive testing (CAT) can enable precise assessment of fatigue using a small number of items from a fatigue item bank. CAT enables brief assessment by selecting questions from an item bank that provide the maximum amount of information given a person{\textquoteright}s previous responses. This article illustrates steps to prepare such an item bank, using 13 items from the Functional Assessment of Chronic Illness Therapy Fatigue Subscale (FACIT-F) as the basis. Samples included 1022 cancer patients and 1010 people from the general population. An Item Response Theory (IRT)-based rating scale model, a polytomous extension of the Rasch dichotomous model was utilized. Nine items demonstrating acceptable psychometric properties were selected and positioned on the fatigue continuum. The fatigue levels measured by these nine items along with their response categories covered 66.8\% of the general population and 82.6\% of the cancer patients. Although the operational CAT algorithms to handle polytomously scored items are still in progress, we illustrated how CAT may work by using nine core items to measure level of fatigue. Using this illustration, a fatigue measure comparable to its full-length 13-item scale administration was obtained using four items. The resulting item bank can serve as a core to which will be added a psychometrically sound and operational item bank covering the entire fatigue continuum.},
	keywords = {*Health Status Indicators, *Questionnaires, Adult, Fatigue/*diagnosis/etiology, Female, Humans, Male, Middle Aged, Neoplasms/complications, Psychometrics, Research Support, Non-U.S. Gov{\textquoteright}t, Research Support, U.S. Gov{\textquoteright}t, P.H.S., Sickness Impact Profile},
	author = {Lai, J-S. and Crane, P. K. and Cella, D. and Chang, C-H. and Bode, R. K. and Heinemann, A. W.}
}
