| Category | Challenges | Supported citations |
---|---|---|---|
1. | Familiarity of flipped classroom | Teachers might not understand the value of flipped classroom and accustomed to this new instructional approach. | Grypp and Luebeck 2015 |
2. | Preparation of flipped classroom | Limited materials (e.g., instructional videos, handouts) were available and suitable for a particular class. | |
 |  | Preparing flipped learning materials required considerable start-up effort. | Chen 2016; Kettle 2013; Kirvan et al. 2015; Snyder et al. 2014 |