Quality of life measurement: one size fits all. Rehabilitation medicine makes no exception

Abstract

Quality of life (QoL) is among the most popular outcome variables in health care, particularly in the field of rehabilitation medicine. Quality may be defined as the ratio between value and cost. However, when applied to people rather than objects, quality remains a controversial concept. For some researchers QoL is an objective status of the person that can be inferred by such indexes as health, education, and social status. For others QoL is a subjective status. Most researchers agree, despite some ethical concerns, that QoL can be measured. This implies assuming that the variable exists. Even under such an assumption one should acknowledge that not all human variables can be measured (e.g., ethnicity and gender). Furthermore, the QoL concept is usually explored by questionnaires summing objective life conditions, satisfaction with life, satisfaction with care, and even functional improvement after minor surgery. Confusion may arise between QoL and other unsuspected variables, unless tools are developed and analysed using modern psychometric approaches such as Rasch analysis, which is rarely the case. As a result, a potential risk is that adhoc arbitrary measures of QoL are used to support decisions regarding the assignment and/or rationing of resources within the welfare system, thus blurring individual responsibility.