Abstract
Quality of life (QOL) is a patient-reported outcome. QOL assessment studies based on psychometrics that target patients have progressed since the 1980s. Clinicians had a desire to use QOL assessments on patients being treated without waiting for QOL assessment results following statistical analysis. This led to the initiation of research on minimal important differences (MIDs) for QOL measurements. MID refers to the minimal difference in QOL score a patient senses in the clinical setting, and is calculated using distribution-based or anchor-based method. With anchor-based method, MID values differ depending on whether QOL worsens or improves. Based on this, anchor-based method is considered more useful for calculating MIDs in the clinical setting. While there remains a need to further debate how to use QOL assessments to maintain and improve QOL, MIDs have utility in the practical use of QOL assessment results for patient and physician decision making.