This NSVRC Evaluation Toolkit webinar introduces preventionists to principles-focused evaluation (PFE), which identifies principles describing core values and behaviors used to foster successful prevention work. PFE complements outcome evaluation and supports decision making during prevention implementation. Viewers will learn how to incorporate their own sexual violence prevention effectiveness principles into their evaluation approach. This learning will be accompanied by examples from Washington state’s experience of engaging preventionists in the process of identifying principles – a project supported by the State Department of Health.