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Psychometric evaluation of a squestionnaire to document side‐effects of chemotherapy
Author(s) -
Sitzia John,
Dikken Clare,
Hughes Jayne
Publication year - 1997
Publication title -
journal of advanced nursing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.948
H-Index - 155
eISSN - 1365-2648
pISSN - 0309-2402
DOI - 10.1046/j.1365-2648.1997.1997025999.x
Subject(s) - cohen's kappa , medicine , stage (stratigraphy) , test (biology) , construct validity , delphi method , clinical psychology , reliability (semiconductor) , psychometrics , statistics , paleontology , power (physics) , physics , mathematics , quantum mechanics , biology
This paper reports the psychometric testing of the Worthing Chemotherapy Questionnaire(WCQ). The WCQ is a patient self‐report instrument to document side‐effects of chemotherapy. Literature review of relevant studies shows that psychometric testing of similar instruments is rarely rigorous. Content validity for the WCQ was established in five ways: literature review, Delphi review among oncology staff, pre‐pilot unstructured interviews, pilot study and amendment of the instrument and items for spontaneous reporting of problems on the questionnaire. A three‐stage approach to construct validity was used. The hypothesis adopted was that as certain cytotoxic agents cause stomatitis, incidence and severity of stomatitis will decrease following cessation of treatment. Stage 1: factor analysis confirmed the presence of a sole factor, with an eigenvalue of 5.3, for mouth problems which explained 65.5% of the variance. Stage 2: the hypothesis was confirmed using research findings. Stage 3: the Wilcoxon test showed highly significant results for during and post chemotherapy stomatitis scores. Reliability of the questionnaire was assessed using the test‐retest method. Weighted Kappa was chosen as the test statistic. A median value of w K=0.87 was obtained. The results indicate that the WCQ is a reliable and valid instrument.