"Rigorous curriculum" refers to an educational program or set of courses that is demanding, challenging, and requires a high level of effort and thinking. Full definition
Regardless of postsecondary goals, all students should be provided with rigorous curriculum, instruction, and assessment. (ccrscenter.org)
A new, more rigorous curriculum was put in place in public schools in 2012 and the impacts of that exploded in classrooms across the state this past year. (wrvo.org)
Other states have had rigorous curricula for a long time. (b4njkids.org)