We present a review of diagnostic testing in the physical sciences. We cover the motivation for using such instruments and their historical development via a case study of probably the most cited and influential test instrument and application: the Force Concept Inventory developed in the early 1990s by Hestenes and co-workers and its use to quantify learning gains from different instructional methodologies by Richard Hake. We then present an overview of the process of creation and validation of such instruments and highlight the results from studies that have made use of some of the many instruments available in the literature. We conclude with a short summary of our own recent work to develop a diagnostic test of data handling skills of physical science undergraduates.
