The process of evaluating treatment plans is complex and qualitative. Treatment planners rely on past experience and expertise to determine when a treatment plan has met its optimal quality, however many factors can degrade that evaluation; the quality of the dosimetrist, their mindset, how busy the clinic is, and the pressure that the dosimetrist feels to complete the planning process. The treatment planners also approach each plan independently and do not have the tools to quantitatively compare the current plan with the previous patients. Studies show that treatment plan quality is often dominated by straightforward geometric features, such as the distance between a target and a neighboring critical structure. This fact has led to the development of dosimetric evaluation features that can be used to 1) characterize each patient based on the geometry of their tumor and organs and 2) provide a subsequent prediction as to how well the planner should be able to do for this patient concerning dosimetric endpoints. Potential applications include improving the overall quality of plans in a clinic, providing a mechanism for comparing different treatment techniques (e.g. arc therapy versus fixed-beam therapy), and comparing plans from different teams or clinics. This panel will provide the state of the art into the development of such metrics and their current uses. At the conclusion of this activity, the learner will be able to do the following: 1. Describe methods for distilling complex treatment planning data into compact treatment plan quality assessment metrics. 2. Explain the potential applications of treatment plan quality assessment metrics. 3. Outline the importance of these metrics to patient safety and treatment quality.