%0 Generic %D 2004 %T The AMC Linear Disability Score project in a population requiring residential care: psychometric properties %A Holman, R. %A Lindeboom, R. %A Vermeulen, M. %A de Haan, R. J. %K *Disability Evaluation %K *Health Status Indicators %K Activities of Daily Living/*classification %K Adult %K Aged %K Aged, 80 and over %K Data Collection/methods %K Female %K Humans %K Logistic Models %K Male %K Middle Aged %K Netherlands %K Pilot Projects %K Probability %K Psychometrics/*instrumentation %K Questionnaires/standards %K Residential Facilities/*utilization %K Severity of Illness Index %X BACKGROUND: Currently there is a lot of interest in the flexible framework offered by item banks for measuring patient relevant outcomes, including functional status. However, there are few item banks, which have been developed to quantify functional status, as expressed by the ability to perform activities of daily life. METHOD: This paper examines the psychometric properties of the AMC Linear Disability Score (ALDS) project item bank using an item response theory model and full information factor analysis. Data were collected from 555 respondents on a total of 160 items. RESULTS: Following the analysis, 79 items remained in the item bank. The remaining 81 items were excluded because of: difficulties in presentation (1 item); low levels of variation in response pattern (28 items); significant differences in measurement characteristics for males and females or for respondents under or over 85 years old (26 items); or lack of model fit to the data at item level (26 items). CONCLUSIONS: It is conceivable that the item bank will have different measurement characteristics for other patient or demographic populations. However, these results indicate that the ALDS item bank has sound psychometric properties for respondents in residential care settings and could form a stable base for measuring functional status in a range of situations, including the implementation of computerised adaptive testing of functional status. %B Health and Quality of Life Outcomes %7 2004/08/05 %V 2 %P 42 %8 Aug 3 %@ 1477-7525 (Electronic)1477-7525 (Linking) %G eng %M 15291958 %2 514531 %0 Generic %D 2004 %T Practical methods for dealing with 'not applicable' item responses in the AMC Linear Disability Score project %A Holman, R. %A Glas, C. A. %A Lindeboom, R. %A Zwinderman, A. H. %A de Haan, R. J. %K *Disability Evaluation %K *Health Surveys %K *Logistic Models %K *Questionnaires %K Activities of Daily Living/*classification %K Data Interpretation, Statistical %K Health Status %K Humans %K Pilot Projects %K Probability %K Quality of Life %K Severity of Illness Index %X BACKGROUND: Whenever questionnaires are used to collect data on constructs, such as functional status or health related quality of life, it is unlikely that all respondents will respond to all items. This paper examines ways of dealing with responses in a 'not applicable' category to items included in the AMC Linear Disability Score (ALDS) project item bank. METHODS: The data examined in this paper come from the responses of 392 respondents to 32 items and form part of the calibration sample for the ALDS item bank. The data are analysed using the one-parameter logistic item response theory model. The four practical strategies for dealing with this type of response are: cold deck imputation; hot deck imputation; treating the missing responses as if these items had never been offered to those individual patients; and using a model which takes account of the 'tendency to respond to items'. RESULTS: The item and respondent population parameter estimates were very similar for the strategies involving hot deck imputation; treating the missing responses as if these items had never been offered to those individual patients; and using a model which takes account of the 'tendency to respond to items'. The estimates obtained using the cold deck imputation method were substantially different. CONCLUSIONS: The cold deck imputation method was not considered suitable for use in the ALDS item bank. The other three methods described can be usefully implemented in the ALDS item bank, depending on the purpose of the data analysis to be carried out. These three methods may be useful for other data sets examining similar constructs, when item response theory based methods are used. %B Health and Quality of Life Outcomes %7 2004/06/18 %V 2 %P 29 %8 Jun 16 %@ 1477-7525 (Electronic)1477-7525 (Linking) %G eng %9 Comparative StudyResearch Support, Non-U.S. Gov't %M 15200681 %2 441407