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The influence of decisions made by developers on health status questionnaire content
1Division of Physiological Medicine, St. George's Hospital Medical School, London, UK.
Insights
Selecting items for health status questionnaires is sensitive to criteria stringency. Even minor variations in selection criteria significantly impact the final content of health questionnaires.
Area of Science:
- Health Outcomes Research
- Psychometrics
- Medical Informatics
Background:
- Developing health status questionnaires requires careful item selection.
- The criteria used for item selection can influence the final questionnaire content.
Purpose of the Study:
- To investigate how stringent versus lenient item selection criteria affect the development of health status questionnaires.
- To determine the impact of varying association thresholds on item pool reduction.
Main Methods:
- Administered a 179-item pool to 139 patients with left ventricular dysfunction.
- Examined item associations with demographic and clinical variables (gender, age, disease duration, global health, global impairment).
- Applied four levels of stringency for item selection based on shared variance thresholds.
Main Results:
- The most stringent criteria (e.g., <=4% shared variance with demographics) selected 75 items.
- The most lenient criteria (e.g., <=6% shared variance with demographics) selected 127 items.
- Small changes in selection criteria thresholds led to substantial differences in the number of selected items.
Conclusions:
- The stringency of selection criteria critically influences the content of health status questionnaires.
- Researchers must carefully consider the chosen thresholds for item selection to ensure appropriate questionnaire development.
- Item selection methodology significantly impacts the resulting health status measure.
Abstract:
To investigate the effect of stringent and lenient criteria upon the process of item selection in the development of a health status questionnaire, an item pool (179 items) was administered to 139 patients with left ventricular dysfunction. Associations between each item and the criteria of gender, age, duration of disease, global health and global impairment were examined. Items were selected from the pool on the basis of their associations with the criteria using four levels of stringency. The most stringent criteria rejected items which had a shared variance of > or = 4% with gender, age and duration of disease and a shared variance of > or = 6% with global health and impairment. The most lenient criteria rejected items which had a shared variance of > or = 6% with gender, age and duration of disease and a shared variance of > or = 4% with global health and impairment. Using the most stringent criteria, 75 items were selected, compared with 127 items using the most lenient criteria. Small differences in the level of association had large effects on item selection. The choice of level of association used to base item selection can have a crucial influence on questionnaire content.