Leave checkboxes for last - start with evidence and reasoning.

In my time teaching, I've coached baseball, football, tennis... and debate.

A common way of teaching students to structure an argument is via “claim, evidence, reasoning.” The debate team uses this in their cases – it’s an excellent way to communicate. The AP exam often encourages this structure by first asking you to check a box to indicate your answer; then, to justify your answer.

To many of you, this brings back bad memories of your 7th grade math class. You knew the answer instantly, because good smart boys and girls always know the answer. And you knew that the teacher knew the answer. But your teacher marked you wrong – “you need to show your work.”  What? Why? This is stupid, I really need to show you how I solved “7-x=3” for x?  The answer’s 4. Justify my answer? Because math and logic. Duh.

And this teachery obsession with “showing your work” extended throughout much of high school.  Okay, the problems got harder, but you still could do them without laying out reasoning step by step as if you were a stupid person. Teachers are so condescending.

Except.

In physics, good smart boys and girls aren’t expected to know the answer. In fact, the teacher doesn’t know the answer to a new physics problem.

Really – I’ve been doing physics since 1990. When I see a free response question, I don't know the answers. I figure them out – I start with facts of physics, continue with an energy bar chart or free body diagram, and come to a conclusion.  

I don't do “claim-evidence-reasoning.”  I do “evidence-reasoning-claim.”

When my students do test corrections, they invariably get hung up on the right answer. They might convince themselves that the answer is that the amplitude increases after the collision.  Then they twist and turn facts and equations to show increasing amplitude… and get more and more frustrated with me as I show them their incorrect logic.  Eventually they get every logical step correct, and say “therefore the amplitude increases."

It never occurs to them that their conclusion might be wrong!

My students are like the evil prosecutors on shows like Law & Order or Matlock… we know this person is guilty, how can we arrange the evidence to convince the jury of their guilt?

That’s not how it should work!  You start with the evidence – based on this information, who is most likely to have committed the crime?  Perhaps if more lawyers and police officers were physics majors, our criminal justice system might be improved.

So don’t be the evil prosecutor. Don’t identify the murderer and then cook the evidence to frame them. Instead, on the AP exam, leave the checkboxes blank until you’ve written your justification.  Then, only then, come to a conclusion – and check the box to say whodunnit.