The validity and reliability of the Turkish version of the Quality of Life Index [QLI] (Cancer version)

Abstract 

Purpose

Quality of life always has become an important concern in the health care of cancer patients. This descriptive study was planned to assess the validity and reliability of the Turkish version of Quality of Life Index – Cancer version in the assessment of the quality of life of lung cancer patients.

Method

The validity and reliability of the scale was performed in two phases. Phase I focused on construction of the Turkish version of the instrument and pilot testing. The scale was translated using the back-translation technique. Five nursing experts reviewed the translation for inconsistencies with the original English form. The comprehensiveness and clarity of the scale was assessed with 20 patients. Phase II included factor analysis and psychometric assessment of the scale. The final version of the scale was pretested with 154 cancer patients.

Results

According to the recommendations of the expert panel, some items were revised and modified, and the Turkish version of the scale was created. The content validity index (CVI) was 97%. Patients cited that this questionnaire was easy to read and understood. Differently from the original QLI scale, factor analysis was changed the domain of some items. Test–retest coefficients for items were between 0.63 and 0.95 (p < 0.05). The scale showed high internal reliability, Cronbach’s alpha values for domain varied between 0.63 and 0.85 and was 0.89 for the tool.

Conclusion

The Turkish version of the QLI was sufficient and suitable tool in evaluating the quality of life of lung cancer patients in Turkey.

Keywords: Quality of Life Index – Cancer version, Lung cancer, Validity, Reliability