The EORTC CAT Core-The computer adaptive version of the EORTC QLQ-C30 questionnaire

Area of Science:

• Health Sciences
• Medical Informatics
• Psychometrics

Background:

• Patient-reported outcome measures (PROMs) require adaptation for individual studies while maintaining score comparability.
• Computerised adaptive tests (CATs) and item banks offer a solution for optimizing PROMs.
• The European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) is a widely used PROM in cancer research.

Purpose of the Study:

• To develop CAT versions of the 14 functional and symptom domains of the EORTC QLQ-C30.
• To create a more precise, powerful, and flexible measurement system for cancer patient quality of life.

Main Methods:

• A systematic strategy for developing CAT item banks, including literature searches, item formulation, expert reviews, and patient interviews.
• Field-testing involving 9782 patients across 12 countries over eight data collection rounds.
• Psychometric analyses using item response theory (IRT) calibration and measurement property simulations.

Main Results:

• Development of 14 item banks with 7-34 unique items each.
• Psychometric evaluations demonstrating higher measurement precision and statistical power compared to traditional QLQ-C30 scales.
• CAT measures can reduce sample size requirements by approximately 20-35% without compromising statistical power.

Conclusions:

• The EORTC CAT Core is a superior measurement system to the QLQ-C30, offering enhanced precision, power, and flexibility.
• The EORTC CAT Core is currently undergoing validation in a large, independent international cancer patient sample.