Evaluating Content Validity

Principal investigator(s)
Kim Cocks
Adelphi Values
Bollington, Cheshire, United Kingdom
, Colin Johnson
Cancer Sciences, University of Southampton
Southampton, United Kingdom
Project coordinator(s)
Chloe Tolley
Adelphi Values
Bollington, Cheshire, United Kingdom
, Jane Wells
Adelphi Values
Bollington, Cheshire, United Kingdom

Project summary

The EORTC QLQ-C30 is a widely used and well validated instrument that is designed to assess health-related quality of life in patients with cancer. Since the original development of the questionnaire in 1987 the treatment landscape has changed and also different methodology for developing instruments has emerged as standard. In order to collect additional information to support the content validity of the EORTC QLQ-C30, new interviews with patients are being conducted to confirm the content validity of the QLQ-C30.

The overall objective of the study is to collect evidence to address the extent to which the QLQ-C30 reflects the issues relevant to cancer patients given the original intended conceptual framework.

A total of 120 qualitative semi-structured interviews lasting approximately 60-90 minutes are being conducted.  Patients will be recruited from sites across Europe and the United States (US). The interview consists of three sections: open ended concept elicitation, more structured discussion of the QLQ-C30 domains, and debriefing of the QLQ-C30. Qualitative thematic analysis is being conducted and results disseminated via publication and conferences.


An initial review of the EORTC disease-specific modules has been completed. This was presented at the ISOQOL conference in 2016.

The methodology for confirming content validity of existing legacy instruments was presented at ISOQOL in 2017.

Recruitment is complete and closed with a total of 113 interviews conducted in the USA, UK, Germany, Netherlands, Poland and Italy.

The analysis is complete and the report has been drafted.

Recruitment is closed. The report is being finalised.

Future plans

The findings will be disseminated in 2020-21

For patients

The EORTC QLQ-C30 is a questionnaire that is designed to measure the quality of life of people with cancer. This questionnaire was originally written in 1987. Since then new cancer treatments have been developed and this work will check it still asks questions that are important and relevant for cancer patients today. A total of 120 people with different types of cancer from Europe and the United States are being interviewed.