• 1 Universiti Sains Malaysia


Health traditionally has been compared using mortality and morbidity and in recent years health related instruments have been utilized along to complement those measures. Health related quality oflife instruments are important because they provide patient's opinion and decision of management and for monitoring and evaluating health status. The quality of life instruments such as health related quality of life questionnaires are increasingly being used and these questionnaires are classified into disease specific and generic questionnaires. They require proper assessment using psychometric analysis of reliability and validity, For reliability, the two common analyses are the test-retest and internal consistency and for validity, it requires the assessment of content validity and analyses of construct validity and criterion validity. Reliable and valid quality of lhfe questionnaires provide consistent and accurate information. The purpose of this paper is to provide crucial assessment and analyses of the reliability and validity of health related quality of life questionnaires.