In their introductory text on teaching, Kauchak and Eggen (2008)Kauchak, D., and Eggen, P. (2008). Introduction to teaching: Becoming a professional (3rd ed.). Upper Saddle River, NJ: Pearson Education, Inc. explain classroom management in terms of time management. The goal of classroom management, to Kauchak and Eggen, is to not only maintain order but to optimize student learning. They divide class time into four overlapping categories, namely allocated time, instructional time, engaged time, and academic learning time.
Allocated time
Allocated time is the total time allotted for teaching, learning, and routine classroom procedures like attendance and announcements. Allocated time is also what appears on a student's schedule, for example "Introductory Algebra: 9:50-10:30 a.m." or "Fine Arts 1:15-2:00 p.m."
Instructional time
Instructional time is what remains after routine classroom procedures are completed. That is to say, instructional time is the time wherein teaching and learning actually takes place. Teachers may spend two or three minutes taking attendance, for example, before their instruction begins. The time it takes for the teacher to do routine tasks can severely limit classroom instruction. Teachers must get a handle on classroom management to be effective.
Engaged time
Engaged time is also called time on task. During engaged time, students are participating actively in learning activities--asking and responding to questions, completing worksheets and exercises, preparing skits and presentations, etc.
Academic learning time
Academic learning time occurs when students 1) participate actively and 2) are successful in learning activities. Effective classroom management maximizes academic learning time.