Assessment instruments have become ubiquitous within chemistry education. They are used to gauge the impacts of curricular change and understand the relations among student-specific characteristics and course outcomes. As educators and education researchers rely on assessment instrument data to make these and other inferences, the tools must be carefully designed, developed, and evaluated with aspects of validity and reliability of the data being generated in mind. This symposium will bring together presentations about the creation and evaluation of all types of assessment instruments with the goal of informing the chemistry education community about the potential uses of these tools, their limitations, and the evidence that supports the validity and reliability of the data they generate.