The National Assessment of Educational Progress (NAEP) has consistently pioneered new assessment methods in conjunction with developing the psychometric methodologies underlying them. Several NAEP developments-such as complex matrix item sampling designs, the introduction of performance-based items in large-scale assessments, vertical scaling, and an intelligent computer system that produces unique assessment reports for participating jurisdictions in the NAEP Trial State Assessment program-are presented in this chapter along with a discussion of their extensions and applications to other current and future assessment projects.