Back to the Future

Communicating with Computers and Programmers in Introductory Computer Science

Brian C. Ladd

Department of Mathematics, Computer Science, and Statistics
St. Lawrence University
http://it.stlawu.edu/~blad/

It's All Writing

• Computer programs are written
  • Two audiences: human and machine
• Writing across the curriculum offers tools for teaching (and thinking about) writing within academic disciplines
  • Writing to learn
  • Writing to communicate
• There is notable similarity between writing programs and writing papers
• Beginning programming students benefit from making the similarity explicit

Writing Across the CS Curriculum

• Introduction
• Related Work
• Portfolios
• Refactoring
• Phased-implementation
• One-minute Design
• Conclusion

Introduction

• St. Lawrence University
  Canton, NY
  • Small, liberal-arts school
    2000 undergraduate students
  • Strong history in computers
    Networked campus for more than two decades
  • Strong history in writing across the curriculum
• First Year Program
  Decade of work teaching writing to first-year students inside discipline-centric survey courses with an emphasis on research methods
• Faculty development for WAC
  Annual May writing seminars (now May Faculty College)

The Problem

• Writing to communicate relegated to a software engineering course
  WAC advocates started with this exact problem: writing was relegated to "writing" classes such as freshman composition.
• Programming students don't understand the value of rewriting
  Identical problem to that found in beginning writers: they think that War and Peace is a first draft. Understanding the place of editing and rewriting is essential in most disciplines.
• Programming students fail to explore the solution space
  Some beginning writers, too, settle too early into writing a "formal" document before they have considered, in more "informal" ways, what they have to say. Recent programming advances have included an emphasis on early prototyping and building simple mock-ups to permit exploration of the solution space before committing to a given design
• Beginning programmers forget the human audience

Related Work

• Literate Programming
  Imagine prose describing a computer program that includes snippets of the code itself. Imagine extracting the snippets to assemble the program. You're imagining Knuth's Literate Programming style.
• Portfolios
• Rewriting
  • Within one program: refactoring
    "Refactoring" and "agile development" are computer industry buzzwords. Refactoring refers to redesigning and rewriting a program when it is found wanting. Agile development is a methodology using many short release cycles (always thinking "What is the smallest, useful change") rather than one longer release cycle; related to rapid prototyping.
  • Across multiple versions of a project: agile development

Portfolios: Overview

• Introductory course
  • Service (distribution and 4+1MBA)
  • Major introduction
  • Java programming language
  • Bots/videogames
• Portfolios are a collection of all course work with about 30% of the assignments "highlighted" by the student
• Have used it (with less success) in the second and third courses

Portfolios: Assignment

• From the assignment:

At least as important as the presentation of your work is the short (1-2 page) essay discussing trends in your work. The purpose of this essay is two-fold: to make you to go back and review all of your work and to give you a voice in how it is viewed as a whole. Make sure your essay discusses the work and what you learned by doing it. This is your opportunity to explain why you think some particular work is good or bad. It is not enough to say "98% says this work is good." You must evaluate your work individually and as a whole.

...Yes, it is all writing and this is your chance, after some small remove, to go back and read your work, looking at it with a critical eye to discuss what went well, what didn't, and what you should be writing in the future.

Portfolios: Assessment

• The Good
  • Fits well with class evaluations
    Students create their portfolio (and essay) at about the same time they do class/instructor evaluations. This is a good time for them to do it as it points out that the success/failure of the class is based on both the instructor and the student.
  • Students generally take the self-assessment seriously and sometimes spot trends even the instructor missed
  • Difficult to plagiarize
    This is an important piece of many assignments we design; it is far better to design an assignment to be difficult to cheat on than it is to have to punish students that cheat on easily plagiarized assignments. Portfolios and rewrites (of both kinds) give the instructor access to student work product at multiple phases; this means that in order to cheat the student must procure intermediate work product as well as the finished product to turn in.
• The Bad
  • Some students see it as busy work; most rely on grades to spot trends
  • Self-assessment is back-loaded
    Assignment is read in class on the first day and referred to through out the semester but students don't assemble the portfolio product until the end of the semester. The self-evaluation essay is written once rather than once every semester (or at midterm and end of semester).
• Future Directions
  • Simplify keeping of the portfolio (SLU infrastructure)
  • Consider expanding to other courses

Portfolios: Student Response

"I'm just used to writing code that generally the only other people reading are myself, or people who are in contact with me, so I can answer any questions they might have. [The lack of comments] is something I will have to work on."

- James Tallett, 2004

Refactoring: Overview & Assignment

Refactoring is the process of rewriting written material to improve its readability or structure, with the explicit purpose of keeping its meaning or behavior.

Wikipedia(Refactoring)

• Refactoring is rewriting to communicate
• Rewriting in first several CS courses is based on a graded "first draft"; students decide whether or not they want to rewrite the project
• 80% of students rewrite at least one project; 20% rewrite more than 3

Refactoring: Assessment

• The Good
  • Students feel greater ownership of their grade
  • Students have a reason to return to a "finished" subject
• The Bad
  • Students only see the grade
  • Rewrites crunch the time (student and instructor)
  • Students only address marked up portions rather than entire program
• Future Directions
  • Look at ungraded (but marked up) first drafts
  • Require students to rewrite a certain number of drafts
  • Reduce the number of required drafts

Refactoring: Student Response

"My grades were almost as high in the end of the semester amidst very complicated programs as they were in the very beginning, in which we were just learning elementary concepts. Although, granted, the frequency of rewrites did increase."

- Lucas Mihuta, 2001

"Being able to do re-writes of the programs was very helpful as well because it gave you the opportunity to really see what you did wrong and how to do it correctly."

- Anonymous Student Evaluation, 2002

Phases: Overview and Assignment

• Larger projects can be assigned in parts
  • Students see the whole project
  • Project is broken into separate phases (each the smallest part that does something interesting)
  • Each phase builds on previous phases; can require refactoring
• One very successful example: CS1.5's text adventure game
  • Semester long building of a text-adventure game from scratch
  • Broken into 9 phases: 3 design phases, 5 implementation phases, and a final extension phase

Phases: Assessment

• The Good
  • Students do rewrite their previous assignments
  • This is how it is in the "real world"
• The Bad
  • Not enough time (between phases) for complete refactoring; making it "good enough" is, well, good enough
  • Students don't rework design phases even when they are changed in subsequent phases
• Future Directions
  • Add more time to assignments if possible
  • See about using this model in introductory course

Phases: Student Response

"Very challenging assignment with learning C++. Need to have longer phases, fewer non-project assignments, or both."

- Anonymous Student Evaluation, 2004

1-M Designs: Overview

• Based on one-minute essays, the one-minute design is a short writing exercise to get the student's mind working on a project
  • A problem is described and students have one minute to design a solution
  • Solution is then turned in or used as the basis of class discussion
  • Example of writing to learn in the CS curriculum
• Specifically not a programming exercise

1-M Designs: Assignment

• Example assignment:

Supernatural Horror, Inc.

The old mansion where our game takes place has several different types of inhabitants including guard dogs, ghosts, and vampires.

Attributes include strength, health, and agility.

In one (1) minute, sketch out a simple class structure for the given Critters; make note of what methods should be included to support combat.

1-M Designs: Solutions

• Assignment is given the class period after the introduction of inheritance and many students draw an inheritance tree; some even use virtual functions
• Student discussion following assignment is well focused
• Students who complete this assignment typically do extend their program with inheritance though few use virtual functions

1-M Designs: Assessment

• The Good
  • Students engage the problem
  • Multiple designs can be discussed
  • Students are not highly invested in their design
• The Bad
  • Weaker students are not helped
  • Sometimes hard to find good places to use
    When there in only one obvious design, students produce a monoculture; this is not good as it can be seen as the norm. When a problem is completely novel, all students can have a hard time getting their heads around it
• Future Directions
  • Find other uses of "writing to learn" or informal writing to use in the CS classroom
    I have read papers about the use of journals or letters in mathematics and computer science instruction. The assignments always seem forced ("The dean says we support writing across the curriculum so write a letter to your best friend back home about the fundamental theorem of calculus" or equivalent). Students only take seriously that which they can see fitting into what they are learning. While the letter on the Fundamental Theorem might actually help the student understand th theorem, it seems unlikely that most students would take the assignment seriously enough to benefit.
  • Use one-minute design at more different levels: high-level design down to method-level design.

Conclusion

• Students benefit from making the similarities between programming and "regular" writing explicit
  • Apply what they know about writing
  • Understand the importance of two audiences
  • See the importance of rewriting
  • Reflect on the actual task
• Computer science instructors benefit from the use of WAC tools such as
  • One-minute designs
  • Rewrites
  • Portfolios

References

Estell, J. "Programming portfolios on the Web: and interactive approach," Journal of Computing in Small Colleges, Volume 16, Number 1. Consortium for Computing Sciences in Colleges. 2000.

Hunt, A and Thomas, D. The Pragmatic Programmer. Addison-Wesley. 1999.

Ladd, B. "It's all writing: experience using rewriting to learn in introductory computer science," Journal of Computing in Small Colleges, Volume 18, Number 5. Consortium for Computing Sciences in Colleges. 2003.

Van Wyk, C. "Programming as writing: using portfolios" SIGCSE Bulletin. Volume 27, Number 4. ACM Press, New York, NY, USA. 1995. http://doi.acm.org/10.1145/216511.216533

Young, A. Teaching Writing Across the Curriculum, 3E. Prentice Hall. 1999.