Abstract
21st century learning requires students to have critical thinking skills, creative, collaboration and communication. These 21st century skills are acquired from the learning process and assessed through formative assessment. Formative assessment is carried out during the learning process. Researchers conducted a literature review review of formative assessment topics. Literature study data were taken from Google Scholar and ERIC in 2015-2023. The articles obtained were as many as 20 articles and then grouped by year of publication, subject, research design and research object. The results of the study showed that the most scientific publications of articles were found in 2019-2020. This formative assessment is widely used in physics subjects. This study uses a lot of quasi-experimental designs. The object of research is widely used on students' conceptual understanding abilities.