Table 4.

Proposed thresholds (and their key sources) for interpreting meaningful improvement and deterioration on key EORTC domain scores

EORTC domain score	Number of items	Minimum score step	Improvement	Deterioration
EORTC QLQ-C30 Physical Functioning	5	6.67	+13.33 (ECDF)	−13.33 (SEM)
EORTC QLQ-LC13 Dyspnea	3	11.11	−11.11 (classification statistics)	+11.11 (classification statistics)
EORTC QLQ-LC13 Coughing	1	33.33	−33.33 (classification statistics)	+33.33 (ECDF and classification statistics)
EORTC QLQ-LC13 Pain in Chest	1	33.33	−33.33 (classification statistics)	+33.33 (ECDF and classification statistics)

ECDF empirical cumulative distribution function, EORTC European Organisation for Research and Treatment of Cancer, QLQ-C30 30-item core instrument, QLQ-LC13 13-item lung cancer module, SEM standard error of measurement