In recent years the educational community has increasingly embraced digital technologies for the purposes of developing alternative learning environments, providing diagnostic feedback, and fostering the development of so-called 21st-century skills. This special issue is dedicated to bridging recent work from the disciplines of educational and psychological assessment and educational data mining (EDM) via the assessment design and implementation framework of "evidence-centered design" (ECD). It consists of a series of five papers: one conceptual paper on ECD, three applied case studies that use ECD and EDM tools, and one simulation study that relies on ECD for its design and EDM for its implementation. In this introduction, we discuss the underlying rationales for the special issue in more detail, provide a short introduction to ECD, and describe the focus of the five selected papers.