This article explains the function of assessment in learning and development, defines the key concepts and principles of assessment, and outlines the responsibilities of the assessor. It also identifies the regulations and requirements relevant to assessment, compares the strengths and limitations of a range of assessment methods, and summarises key factors to consider when planning assessment. Additionally, it evaluates the benefits of using a holistic approach to assessment, explains how to minimise risks through planning, and discusses the importance of involving the learner and others in the assessment process. Finally, it explains how to judge whether evidence is sufficient, authentic, and current, and how to ensure that assessment decisions are made against specified criteria, valid, reliable, and fair. It also summarises quality assurance and standardisation procedures, procedures to follow when there are disputes concerning assessment, legal issues, policies, and procedures relevant to assessment, and the contribution that technology can make to the assessment process.