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.
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.
Authors: John E Ware; Mark Kosinski; Jakob B Bjorner; Martha S Bayliss; Alice Batenhorst; Carl G H Dahlöf; Stewart Tepper; Andrew Dowson Journal: Qual Life Res Date: 2003-12 Impact factor: 4.147
Authors: Morten Aa Petersen; Mogens Groenvold; Neil K Aaronson; Wei-Chu Chie; Thierry Conroy; Anna Costantini; Peter Fayers; Jorunn Helbostad; Bernhard Holzner; Stein Kaasa; Susanne Singer; Galina Velikova; Teresa Young Journal: Qual Life Res Date: 2010-10-23 Impact factor: 4.147
Authors: M Kosinski; M S Bayliss; J B Bjorner; J E Ware; W H Garber; A Batenhorst; R Cady; C G H Dahlöf; A Dowson; S Tepper Journal: Qual Life Res Date: 2003-12 Impact factor: 4.147
Authors: John E Ware; Mark Kosinski; Jakob B Bjorner; Martha S Bayliss; Alice Batenhorst; Carl G H Dahlöf; Stewart Tepper; Andrew Dowson Journal: Qual Life Res Date: 2003-12 Impact factor: 4.147