ABSTRACT
Once the decision has been made by a clinical investigator or practitioner to measure quality of life, the next question is how to do it. This chapter provides a simple algorithm, or decision tree, as a step-by-step approach that can serve as a guide for the selection of appropriate methods and instruments. It provides a checklist of properties or criteria that need to be considered when examining questionnaires to be completed either by health care professionals or as self-assessment instruments. An algorithm is a step-by-step set of guidelines for solving a complex problem by setting down individual steps and showing how each step follows the preceding one. Screening is the systematic examination of a large group of individuals in order to identify those displaying certain characteristics. In preference assessment, patients are asked to express their preference for a particular health state. There are two main methods for assessing quality of life: by interviews and by questionnaires.
