Order effects: a randomised study of three major cancer-specific quality of life instruments.
Cheung, Yin-Bun;
Lim, Celestine;
Goh, Cynthia;
Thumboo, Julian;
Wee, Joseph;
(2005)
Order effects: a randomised study of three major cancer-specific quality of life instruments.
Health and quality of life outcomes, 3 (1).
37-.
ISSN 1477-7525
DOI: https://doi.org/10.1186/1477-7525-3-37
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BACKGROUND: In methodological studies and outcomes research, questionnaires often comprise several health-related quality of life (HRQoL) measures. Previous psychological studies have suggested that changing the sequential order of measurement scales within a questionnaire could alter the pattern of responses. Yet, information on the presence or absence of order effects on the assessment of HRQoL in cancer patients is limited. METHODS: An incomplete block design was used in this study of 1277 cancer patients. Each patient filled out a questionnaire package that contained two of the three major cancer-specific HRQoL instruments, namely the Functional Assessment of Cancer Therapy--General, the European Organization for the Research and Treatment of Cancer Core Quality of Life Questionnaire and the Functional Living Index--Cancer. Within a questionnaire package the sequential order of the instruments contained were randomised. Measurement properties of the instruments, including the number of missing values, mean HRQoL scores, known-groups validity and internal consistency were compared between samples of different presentation orders. RESULTS: No effect of presentation order on the four properties aforementioned was found. CONCLUSION: Presentation order is unlikely to alter the responses to these HRQoL instruments administered in cancer patients when any two of them are used together.
