EORTC CAT

The EORTC QLG has developed a computerized adaptive testing (CAT) verison of the EORTC QLQ-C30.

The basic idea of CAT is to maximize the information obtained through questionnaire administration by adapting the questionnaire to the individual respondent. This is done by using the responses to the previously posed items to select the most informative next item.

CAT has several advantages including increased precision, reduced floor and ceiling effects, avoidance of non-informative questions, and increased flexibility.

 

The EORTC CAT instrument will measure the same well-validated and well-known HRQOL domains/dimensions as measured with the existing EORTC QLQ-C30. For each QLQ-C30 dimension a so-called item bank, from which the CAT selects the items for each patient, is developed. These item banks consist of items covering the same domain content as the QLQ-C30. The new items will have the same item and response format as the QLQ-C30 items. A common scoring system will ensure that results can be compared across the two measurement systems, i.e. between studies using the traditional QLQ-C30 and the new EORTC CAT. In particular, studies using the CAT will be backward-compatible with QLQ-C30 data collected in earlier studies.

 

The QLG has completed the development of item banks for all functional and symptom domains of the QLQ-C30. The EORTC CAT is currently being validated in an international, clinical validation study. Despite very encouraging results as documented in the published papers (see here) the item banks should be viewed as “experimental” until the clinical validation has been completed. Therefore, they should not yet be used as sole outcome measures in studies. Currently, we recommend using the EORTC CAT item banks together with the original QLQ-C30. Further details on how to use this “experimental” EORTC CAT are available here.