In this digital ITEMS module, Dr. Robert [Bob] Mislevy and Dr. Maria Elena Oliveri introduce and illustrate a sociocognitive perspective on educational measurement, which focuses on a variety of design and implementation considerations for creating fair and valid assessments for learners from diverse populations with diverse sociocultural experiences. The first part of the module, narrated by Dr. Mislevy, contains a general overview section, a description of the sociocognitive framing of assessment issues, and a section on implications for assessment around key concepts such as reliability, validity, and fairness. The second part of the module, narrated by Dr. Oliveri, contains a section on frameworks for fairness investigations and principled assessment design as well as brief vignette-based illustrations of the principles using a prototype activity to support collaboration and communication skills in the workplace. The module is designed to provide a relatively high-level, conceptual, and nonstatistical overview and is intended for interdisciplinary team members who need to create fair and equitable learning and assessment systems for diverse populations.