Quality of Life Research

, Volume 12, Issue 8, pp 913–933

Calibration of an item pool for assessing the burden of headaches: An application of item response theory to the Headache Impact Test (HIT™)

  • Jakob B. Bjorner
  • Mark Kosinski
  • John E. Ware Jr
Article

DOI: 10.1023/A:1026163113446

Cite this article as:
Bjorner, J.B., Kosinski, M. & Ware Jr, J.E. Qual Life Res (2003) 12: 913. doi:10.1023/A:1026163113446

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.

Computerized adaptive testing Disability Headache Health status Impact Item response theory Migraine Quality of life Questionnaires Severity Tension headache 

Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • Jakob B. Bjorner
    • 1
    • 2
  • Mark Kosinski
    • 1
  • John E. Ware Jr
    • 1
    • 3
  1. 1.QualityMetric IncorporatedLincolnUSA
  2. 2.National Institute of Occupational HealthCopenhagenDenmark
  3. 3.Health Assessment LabWalthamUSA

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