Adult education is a key policy to achieve the sustainable development goals. Large-scale open online courses are gradually increasing with the continued spread of COVID-19 all around the world, which has also attracted more and more adults to participate in such courses. However, despite the fact that the research on adult online learning is abundant, there is still a lack of systematic summaries that can guide the design and selection of course content and instructional methods. Therefore, the purpose of this study is to systematically examine the factors and related strategies that influence adult online learning, and to some extent also provide directions for future research. Using a systematic literature review, with the help of literature visualization software CiteSpace, this study summarized and analyzed 124 SSCI literature of empirical studies. The findings show that although some conclusions of adult online learning research are controversial, there is still some consensus, which is worthy of our attention. First, adult learners have time constraints and more responsibilities, hence life oriented, structured, and flexible online courses are more suitable for them. Secondly, adult learners have less scholastic aptitude and are less ICT skilled than normal students, so preparatory learning is necessary. Finally, in terms of an online instructional approach, integrated online discussions are recommended, as adults are prone to inefficient and superficial discussions in open discussions. This study contributes to theory and practice by expanding the systematic understanding of online learning for adults.

Teachers’ informatization teaching ability (TITA) is the core ability of teachers to engage in educational activities in the informatization environment. It is an essential indicator of the quality of education and affects teachers’ professional development in the technological age. To get a precise teachers’ informatization teaching ability scale and to measure TITA more accurately, the quality of existing scales needs to be improved. This study analyzed and generalized definitions, models and frameworks for TITA, proposed a four-dimension model (teachers’ informatization teaching metacognitive ability, informatization teaching design ability, informatization teaching implementation ability and informatization teaching evaluation ability), and developed the TITA scale. Three experts were involved in the content validity of the TITA scale process. A total of 403 valid questionnaires answered by Chinese primary and secondary school teachers were used to test the reliability and convergent validity of the scale. The results showed that the TITA scale has high reliability and good validity, and it can be used to evaluate TITA in future studies. The TITA scale also provided a theoretical framework to help teachers consider how to transfer knowledge and skills to students by various technologies more effectively.