Validity and reliability of single-item self-report measures of general quality of life, general health and sleep quality

University of Gdańsk, National Science Centre Poland

Different aspects of quality of life are important variables in the study of wellbeing and psychosocial functioning. For that reason, measurement of quality of life is indispensable in any researches related to health or wellbeing, which are often large scale surveys, frequently including repeated measurements. Hence, valid and easily applied measures are essential. Self-report questionnaires of different aspects of quality of life are often lengthy, which may result in a substantial burden to participants and a threat to the validity of measurement due to the effects of fatigue. To overcome these difficulties validity and reliability of single-item, self-report measures of general quality of life, general health and sleep quality were examined in a sample of 1451 university students. These three measures were administered in a subsample of 135 students on two occasions with three weeks interval between them. Intraclass correlation coefficients (ICC) for test-retest reliability were mostly high and all were satisfying, .86 for general quality of life, .72 for general health and .81 for sleep quality. All measures were related in predictable ways to perceived stress, depressiveness, anxiety, loneliness and daily hours of sleep. The study provides evidence for the validity and reliability of these single-item measures. These scales are potentially convenient measures of general quality of life, general health and sleep quality in large surveys.