This paper summarises the key messages from NRDC and other research and development activity on formative assessment in adult learning. This has been an under-researched area: much of the work on formative assessment in the UK and internationally has been carried out in compulsory or higher education. While this has generated a solid evidence base supporting the usefulness of formative assessment and identifying general techniques and activities that teachers can use with their students, until recently there had not been an attempt to relate these ideas to adult learning or to review the literature to learn how formative assessment can work with adult learners. However, recent research suggests that formative assessment may be particularly useful for adult learners, in a variety of settings. This short paper explores research on the use of formative assessment, discusses what formative assessment is and is not, briefly explains some key formative assessment strategies, and looks at challenges to the expanded use of formative assessment in adult learning.