Background The McGill Quality of Life Questionnaire - Expanded (MQOL-E) and the Quality of Life in Life-Threatening Illness-Family Carer/Caregiver version (QOLLTI-F) are developed for use with patients facing the end of life and their family carers, respectively. They are also developed for possible use as companion instruments. Contemporary measurement validity theory places emphasis on response processes, i.e. what people feel and think when responding to items.