Vascular malformations are congenital anomalies of the vascular and/or lymphatic system that affect the head and neck region. The most common treatment options are sclerotherapy, laser therapy, surgery, and embolization. Because vascular malformations are variable in type, size, extent, and location, it is a challenge to select methods for evaluation of treatment outcome. Without standardized outcome reporting, it is difficult to compare and combine scientific evidence to support therapeutic decision making. Standardized collection and reporting of outcome data are the first steps toward a fair comparison between treatments. This article describes outcome measurements for vascular malformations and initiatives to improve outcome reporting.