Assessment Systems is a United States-based company established in 1979, specializing in the education sector, particularly in training and e-learning services. With a workforce of 11 to 50 employees, the company focuses on developing tools and resources that support educational assessments. One of their notable publications is the "NBME Item-Writing Guide," which serves as a comprehensive resource for constructing written test questions specifically tailored for the health sciences. This guide emphasizes the importance of assessment as a crucial component of instruction, discussing various aspects such as the format and structure of test items, the purposes of testing, and the significance of ensuring that test items are representative of the broader content domain. The document highlights issues related to test reliability and validity, underscoring the need for careful consideration in test design to avoid biases and ensure accurate measurement of achievement. Overall, Assessment Systems engages in creating educational materials that facilitate effective assessment practices within the health sciences and beyond.