Lecture formats allow an instructor to stay on topic. Often class discussions veer off topic, and students contribute less than relevant remarks or repeat other students' comments, sometimes only for the sake of participating. But with lecture, the instructor is able to control the material and keep the class focused on what is important.
Lectures are more efficient than textbook reading or class discussion, since the instructor synthesizes, summarizes and reports the most essential parts of a lesson or chapter. Because lectures are prepared, the instructor can deliberately condense material and include only the most relevant and pertinent material, which is especially useful in classes in which there is a lot of ground to cover in a short amount of time. Further, the instructor, aware of audience, can anticipate student concerns or questions and prepare to go into more depth or detail about topics that may be confusing or more difficult to understand, while glossing over topics that are easy to grasp.
With lecture format, the instructor has control over the learning experience. Controlled lecture methods meet the needs of students that learn best in very structured, teacher-centered settings. Additionally, the instructor is not required to deal with unanticipated student comments, whether they be off-topic, offensive to the teacher or to other students, or otherwise inappropriate.
Lectures require middle and high school students to develop their listening skills and attention spans, which are essential skills in post-secondary education and beyond the classroom. Chances are, college-bound students will confront lecture-styled courses at the undergraduate level, and students who pursue professional work -- whether immediately upon high school graduation or later -- will have to learn from oral presentation formats. Therefore, it is important for students to become more attentive listeners and learners, and lecture formats in middle and high school help to accomplish this.