1997 ASEE Annual Conference, Milwaukee, WI, June 1997.

BEATING THE NUMBERS GAME:
EFFECTIVE TEACHING IN LARGE CLASSES

Richard M. Felder
Department of Chemical Engineering
North Carolina State University

Phil Wankat wrote somewhere--and I agree--that anything you can do in a large class you can do better in a small one. When we find ourselves teaching a mob, it's easy to throw up our hands, conclude that there's no chance of getting any responsiveness out of 150 or 300 students in an auditorium, and spend 45 hours showing transparencies to the listless 60% who bother to show up from day to day. We can generate some interest by bringing demonstrations to class, but there are only so many hydrogen balloons we can explode and even they lose their impact after a while.

Fortunately, there are ways to make large classes almost as effective as their smaller counterparts. Without turning yourself inside out, you can get students actively involved, help them develop a sense of community, and give frequent homework assignments without killing yourself (or your teaching assistants) with impossible grading loads. Following are some ideas for doing all that.

In-Class Exercises

Lectures as a rule have little educational value. People learn by doing, not by watching and listening. If you're teaching a small class and you're good, you may be able to prod many of your students into activity--get them asking and answering questions, discussing issues, challenging conclusions, laughing at your jokes, whatever. No matter how good you are, though, you probably won't be able to persuade most students to open their mouths in front of 120 classmates--it feels too risky for them. If you hope to move away from the wax museum-like aspect of most large lectures, you'll have to try a different approach.

A technique you can count on is the in-class exercise. As you lecture on a body of material or go through a problem solution, instead of just posing questions to the class as a whole and enduring the ensuing time-wasting silences, occasionally assign a task and give the students anywhere from 30 seconds to five minutes to come up with a response. Anything can serve as a basis for these exercises, including the same questions you normally ask in lectures and perhaps some others that might not be part of your current repertoire.1 For example,

You might pose a problem or describe a system and ask the students, individually or in groups, to

In these exercises you might sometimes ask the students to write responses individually, sometimes to work in pairs or groups of three, and sometimes to work alone and then to form pairs and combine and improve their individual responses ("think-pair-share"). The more you vary your methods, the more interesting the class tends to be.

Whichever approach you use for the exercises (individual, pairs, groups, or think-pair-share), at least some of the time you should call on groups or individuals to present what they came up with, perhaps landing disproportionately on students near the back of the room so they know they can't hide from you there. If you never do this, students will have little incentive to work on the exercises when you assign them and many won't, but if they think they may be called on, they won't want to be embarrassed and so you'll get 90+ percent of them actively involved in what you're teaching. Even if you're an award-winning traditional lecturer, that's probably better than your usual percentage for active student involvement during class.

The principal benefit of these exercises is that they get students acting and reflecting, the only two ways by which human beings learn. The students who succeed in a task will own the knowledge in a way they never could if you simply handed it to them, and those who try and fail will be receptive to discovering what they didn't know. Group exercises have the added benefit of giving students an opportunity to meet and work with one another, a good first step toward building a sense of community. (You can augment this benefit by periodically asking the students to sit in different locations and work with students they haven't been with before.)

You can also use in-class exercises to wrap up a lecture period. Ask the students to write down and hand in a brief statement of the main point of the lecture, or come up with two good questions or test problems related to what you just presented, or tell you how they think you could improve the class. You can scan their responses and quickly see if they got the main idea you were trying to present, identify their main points of confusion, or discover things you could do that would make the class better for them, like giving more examples or leaving material on the board longer or speaking more slowly or not cracking your knuckles every five seconds.

You don't have to spend a great deal of time on active learning exercises in class: one or two lasting no more than five minutes in a 50-minute session can provide enough stimulation to keep the class with you for the entire period. The syllabus is safe!

Out-of-class Group Assignments

When you're teaching a class of 160 students and you give individual homework weekly, that's 160 papers to grade every week. If the students complete the assignments in teams of four and only one solution is handed in by each team, that's 40 papers to grade every week. The difference has a major impact on the feasibility of collecting homework at all. Unless you have a squadron of teaching assistants, there is no good way to deal with 160 papers every week, and most instructors in this situation either give up on collecting homework (which is a pedagogical disaster), confine themselves to multiple-choice problems that require either memorization or rote substitution, or grade superficially enough for the homework to lose most of its educational value. Even if there are enough teaching assistants to do the job, maintaining quality control on the grading of hundreds of assignments is next to impossible.

Getting students to work on assignments in fixed teams relieves the grading problem but introduces another set of problems, most of which have to do with the fact that the students in a group may have widely varying levels of ability, work ethics, and senses of responsibility. If an instructor simply tells students to get into groups and do the work, more harm than good may result. In some groups, one or two students will actually do the work and the others will simply go along for the ride. In other groups, the students will parcel out the work and staple the individual products together, with each student understanding only one-fourth of the assignment.

To minimize the likelihood of these situations occurring, the instructor must structure the assignments to assure that the defining conditions of cooperative learning3 are met: (1) positive interdependence (if one team member fails to meet his or her responsibilities, everyone loses in some way); (2) individual accountability (each student is held personally accountable for his or her part and for everyone else's part as well); (3) face-to-face interaction, at least part of the time; (4) development and appropriate use of teamwork skills (leadership, time management, effective communication, and conflict resolution, to name a few), and (5) periodic self-assessment of group functioning (What are we doing well as a group? What do we need to do differently?)

Books, articles, and workshops abound that describe techniques for achieving the requisite conditions of cooperative learning.3-5 For example, individual accountability is promoted by testing individuals on all of the material covered in group assignments and by factoring individual effort assessments into team project grading. Positive interdependence is fostered by assigning rotating roles to team members (coordinator, recorder, checker), and by offering small bonuses on tests to all members of teams with average test grades above (say) 80. References 3-5 offer many other suggestions.

Miscellaneous Ideas

Summary

Teaching a large class effectively is hard work, but it's possible to do it even if you're not a big-league entertainer. If you make the necessary logistical arrangements far enough in advance, provide plenty of active learning experiences in the classroom instead of relying on straight lecturing, and take full advantage of the power of teams in both in-class and out-of-class work, large classes can come close to being as educationally rewarding as small classes. The instructor's satisfaction may be even greater in the large classes: after all, many professors can teach 15 students effectively, but when you do it with 100 or more you know you've really accomplished something.

Bibliography

  1. R.M. Felder, "How About a Quick One?" Chem. Engr. Education, 26(1), 18-19 (1992). Formats for in-class exercises.
  2. R.M. Felder, "It Goes Without Saying." Chem. Engr. Education, 25(3), 132-133 (1991). An illustrative lesson utilizing active learning.
  3. D.W. Johnson, R.T. Johnson, and K.A. Smith, Active Learning: Cooperation in the College Classroom, Edina, MN, Interaction Book Co., 1991.
  4. R.M. Felder and R. Brent, Cooperative Learning in Technical Courses: Procedures, Pitfalls, and Payoffs, ERIC Document Reproduction Service, ED 377038 (1994).
  5. R.M. Felder and R. Brent, "Navigating The Bumpy Road to Student-Centered Instruction," College Teaching, 44 (2), 43-47 (1996). Understanding and dealing with student resistance to active learning techniques.

RICHARD M. FELDER is the Hoechst Celanese Professor of Chemical Engineering at North Carolina State University. He is co-author of the introductory chemical engineering text Elementary Principles of Chemical Processes and codirector of the National Effective Teaching Institute.