High-incidence disabilities (HID): Disabilities that are more commonly seen in general education classrooms.

Co-taught classes: Classes in which students are taught by co-teachers, consisting of general and special educators, who collaboratively plan, instruct, and assess a diverse group of students in general education classrooms.

Treatment group: Students in this group received the UDL-based instruction.

Comparison group: Students in this group received the traditional instruction (i.e., techniques and materials that the teachers typically use to teach mole conversion).

Effect size (ES): Effect size is a measure that quantifies the strength of a relationship or difference observed in a study. It gives you an idea of how significant the difference is between groups or the impact of an intervention, beyond just knowing whether it’s statistically significant. Effect size complements p-values by providing more context on the practical significance of the results.