3. Self-perception of wellness or its absence. There are two basic types of instruments for measuring the QOL: generic and disease specific. Generic instruments focus on the main components that constitute QOL, and are intended to be applied in a wide range of populations and health states across all diseases. There are many excellent validated self-completion questionnaires for cancer patients eg. EORTC QOL questionnaire, Functional assessment of Cancer Therapy (FACT), Rotterdam Symptom Checklist (RSCL), Functional Living Index Cancer (FLIC). All these questionnaires are multidimensional, and it is rarely required to develop a new instrument.