Abstract: The ability to measure what students are learning (or not) is a crucial component of crafting effective learning environments. In particular, low-stakes, standardized diagnostic assessments can provide a valuable tool for tracking student learning over time and between instructional approaches to identify effective strategies that improve students' understanding of core physics content. The field of physics education research (PER) has created a number of these assessment instruments targeting content from introductory mechanics up to senior-level thermal physics. While these assessments have provided an important mechanism to ground educational decision making in data on student learning, it is important for these instruments to evolve to meet the needs of a changing educational landscape. In this talk, I will articulate the value of standardized assessments in the context of improving physics programs broadly as well as the need for a new generation of assessment instruments. I will describe work towards meeting these next generation assessment needs for a range of physics content areas.