The quality of working life questionnaire for cancer survivors (QWLQ-CS): factorial structure, internal consistency, construct validity and reproducibility

Abstract

BackgroundTo assess the factorial structure, internal consistency, construct validity and reproducibility of the Quality of Working Life Questionnaire for Cancer Survivors (QWLQ-CS).MethodsAn Exploratory Factor Analysis (EFA) was performed on QWLQ-CS data from a sample of employed cancer survivors to establish the final number of items and factorial structure of the QWLQ-CS. Internal consistency was assessed using Cronbach’s alpha. In a second sample of (self-)employed cancer survivors, construct validity was tested by convergent validity (correlations of QWLQ-CS with construct-related questionnaires), and discriminative validity (difference in QWLQ-CS scores between cancer survivors and employed people without cancer). In a subgroup of stable cancer survivors subtracted from the second sample, reproducibility was evaluated by Intraclass Correlation Coefficient (ICC) and Standard Error of Measurement (SEM).ResultsEFA on QWLQ-CS data of 302 cancer survivors resulted in 23 items and five factors. The internal consistency of the QWLQ-CS was Cronbach’s α = 0.91. Convergent validity on data of 130 cancer survivors resulted in r = 0.61–0.70. QWLQ-CS scores of these cancer survivors statistically differed (p = 0.04) from employed people without cancer (N = 45). Reproducibility of QWLQ-CS data from 87 cancer survivors demonstrated an ICC of 0.84 and a SEM of 9.59.ConclusionsThe five-factor QWLQ-CS with 23 items and adequate internal consistency, construct validity, and reproducibility at group level can be used in clinical and occupational healthcare, and research settings.Electronic supplementary materialThe online version of this article (10.1186/s12885-017-3966-1) contains supplementary material, which is available to authorized users.

The Quality of Working Life Questionnaire for Cancer Survivors: Sufficient responsiveness for use as a patient-reported outcome measurement

“…Interpretability was assessed by comparing the SDC with the MIC at three levels: (a) for the QWLQ‐CS total score and each subscale individually, (b) for use at group and individual level separately, and (c) for improvement and deterioration separately. SDC_ind was derived from the Standard Error of Measurement (SEM_agreement) (de Jong et al, ) using the following formula: (1.96 * √2 * SEM_agreement) (de Vet et al, ) and for use at group level SDC_group = SDC_ind/√(N) (de Vet et al, ). The MIC for improvement and deterioration was based on the mean change method.…”

“…The quality of working life of cancer survivors can be measured with the Quality of Working Life Questionnaire for Cancer Survivors (QWLQ‐CS) (de Jong, Tamminga, van Es, Frings‐Dresen, & de Boer, ), which is a patient‐reported outcome measurement (PROM) that contains 23 items divided into five subscales (de Jong et al, ). A previous study has shown good internal consistency, construct validity, and reproducibility of the QWLQ‐CS (de Jong et al, ). However, to be able to use the QWLQ‐CS as a PROM of an intervention in research or practice, the responsiveness and interpretability of the QWLQ‐CS need to be determined (Mokkink, Terwee, Patrick, et al, ).…”

“…The quality of working life of cancer survivors can be measured with the Quality of Working Life Questionnaire for Cancer Survivors (QWLQ-CS) (de Jong, Tamminga, van Es, Frings-Dresen, & de Boer, 2018), which is a patient-reported outcome measurement (PROM) that contains 23 items divided into five subscales . A previous study has shown good internal consistency, construct validity, and reproducibility of the QWLQ-CS .…”

The Successful Return-To-Work Questionnaire for Cancer Survivors (I-RTW_CS): Development, Validity and Reproducibility

“…Similarities between both questionnaires relate to the measured constructs, i.e. 'quality of working life' and 'successfulness of return to work', and in the recall period of 4 weeks [22]. Differences relate to their usability for self-employed cancer survivors, which applies to the QWLQ-CS [22], but not for the I-RTW_CS, and in the weighting of the items based on their perceived importance for the individual cancer survivor, which only applies to the I-RTW_CS.…”

“…The answer option 'does not apply' for self-employed cancer survivors was omitted, as they were not included in this study. The QWLQ-CS has sufficient to good measurement properties in cancer survivors [22].…”