Pedagogical Pattern #56
Expose The Process

Also here on the Pedagogical Patterns Project web site.

(Version 1.0, April 1999)

Contributed by:
Byron Weber Becker
Department of Computer Science
University of Waterloo
Waterloo, Ontario, N2L 3G1, Canada
bwbecker@uwaterloo.ca

NAME:

Expose The Process

THUMBNAIL:

Students can benefit by watching an idea develop, whether the idea is embodied in a computer program, designing some artifact, or writing a story.  When instructors expose their own thought processes, students can learn the kinds of questions they could ask in their own development efforts.

AUDIENCE/ CONTEXT:

This pattern applies any time a process involving decisions is being discussed.

FORCES:

Students often see examples in their finished form without seeing the process that led to the solutions.  When students are then asked to find solutions to their own problems, they have many misconceptions about the process.  They may think it is supposed to be a linear process when in fact even experts explore dead ends and backtrack before finding an acceptable solution.  Students may not realize that many alternatives must be considered and discarded along the way.  They may not understand the kinds of questions that should be asked when deciding between alternatives.  Sometimes students do not understand that there are several acceptable solutions;  they aim for the correct solution.

Students may become discouraged when they hold their own work (and the process of getting there) up against the finished products seen in class or in a text (especially if the process shown, if any, was linear).  Furthermore, if their own process was linear their finished product will likely fall short of their potential..
 

SOLUTION:

When we show examples (either in class or in a textbook), we should at least occasionally show a realistic process of getting to the solution.  This includes identifying the decision points (as experts we often no longer realize when we're making a decision between alternative approaches), brainstorming the available options, evaluating each option, and finally choosing one. Exploring dead ends and backtracking to previous decisions is also helpful.

DISCUSSION/ CONSEQUENCES/ IMPLEMENTATION:

There are at least two ways for instructors to approach the Expose Yourself pattern.  One way is to do a problem "live".  Go to lecture with a problem identified, but for which you have not worked out a solution.  Work out the solution in front of the students, being as verbal as possible about the decisions being made.  This is a risky approach but may appeal to some.

A safer approach is to choose a problem, working it out before class.  As you work it out, record your decisions in a tree format.  After the solution is finished, review the tree to identify the most crucial decisions -- the ones you will want to dwell on in class.  Perhaps changing the order in which you consider alternatives will make more sense to students.

Be careful with how you involve students.  If asked to suggest alternative solutions, the brighter students may consistently suggest the strongest alternatives first.  This leaves you in the awkward position of suggesting or soliciting obviously weaker solutions.  A better approach is to present some weaker alternatives first, then ask students for other ideas.  Or suggest all of the alternatives yourself, inviting students to help evaluate the pros and cons of each.

It may be helpful to chart your progress on the blackboard as a tree of decisions.  Asking students to log their own decisions during a homework assignment may help them realize just how complex a task they are facing.  It may also help them identify where they are making decisions so they can actively work at identifying alternatives rather than simply going with the first idea they have.

This takes a long time!  Don't rush it; reduce your expectations for what you will "accomplish" in the time you have allotted.  Exposing your thought processes will be accomplishing a lot! It is not necessary to use this pattern for the entire development of a problem.  It could be used at just one decision point, for instance.

SPECIAL RESOURCES:

Careful thought, with enough detachment and introspection to realize when decisions are being made in your own thought processes, is required to work out the example.

RELATED PATTERNS:

This is closely related to the case studies championed by Michael Clancy (see Designing Pascal Solutions: A Case Study Approach by Michael J. Clancy and Marcia C. Linn, W. H. Freeman and Co. 1992.).

EXAMPLE INSTANCES:

  1. This pattern has been used often in the introductory programming course at the University of Waterloo (Waterloo, Ontario, Canada) by the author, Arnie Dyck, Jack Rehder, and others.  At Waterloo the technique is most often used in a lecture format.  The next meeting with the students, called a "Practicum", has the students working in groups of three on a problem similar to that seen in lecture.  This gives students an almost immediate opportunity to put what they have seen into practice.  The group setting helps identify the decision points and encourages discussion of alternatives.
  2. Kamin, Mickunas and Reingold use this pattern several times in their introductory Java text, An Introduction to Computer Science using Java (McGraw-Hill, 1998). See section 6.6, p. 190-197, for instance.

CONTRAINDICATIONS:

Do not use the Expose The Process pattern when introducing a new topic.  It is not fair to the student to go through a drawn out process, showing all the alternatives, and then introducing a new technique at the last moment.  This defeats the point of the pattern -- how to apply tools and techniques students already know to develop an idea. 

Expose The Process serves best in a consolidation week, when students are practicing formerly introduced topics and learning how best to apply them.

ACKNOWLEDGMENTS:

Expose The Process was first identified as a pattern in the Incorporating Patterns into CS Courses workshop at SIGCSE '99.

Arnie Dyck was instrumental in entrenching this pattern at University of Waterloo.