The field of quality-of-life (QOL) measurement grew out of attempts in the 1960s and 1970s to connect the ever-increasing levels of public expenditure on technology-based health care for chronic diseases with evidence of the benefits and harms to patients. Most of the concepts, methods, and standards for measuring QOL were derived from psychometrics, but the degree to which current tools adhere to these methods varies greatly. Despite the importance of QOL, patient-reported outcomes are not measured in most cardiovascular clinical trials. Lack of familiarity with QOL measures and their interpretation, and unrealistic expectations about the information these measures can provide, are obstacles to their use. Large clinical trials of revascularization therapy for coronary artery disease and medical treatments for heart failure show small-to-moderate QOL effects, primarily detected with disease-specific instruments. Larger treatment effects, seen in trials of device therapy for heart failure and ablation therapy for atrial fibrillation, have been detected with both generic and disease-specific instruments. A large gap remains between the parameters currently being measured in clinical research and the data needed to incorporate the 'patient's voice' into therapeutic decision-making.