What are the effects of block scheduling? Results of transitioning from traditional to block scheduling are mixed. Some studies indicate no change in achievement results, nor change in teachers' opinions about instructional strategies. Other studies show that block scheduling doesn't work well for Advanced Placement or Music courses, that "hard to teach" students don't do as well, and that achievement in some subjects declines (e.g.: mathematics conceptual understanding). Other studies indicate improved attitude of teachers and students, improved achievement scores in all subjects, reduced behavior and attendance problems, improved implementation of inclusion practices, improved integration of technology, higher number of credits earned by students. The positive impact of block schedule seemed to hinge on changes to instructional strategies that engaged more learners, and teachers' receiving adequate training in implementing appropriate instructional strategies. (Contains 6 online resources.)