Part 1: The Math of Zero in a Percentage Scale (Tuesday, November 20, 2007)

I was talking to a colleague recently about how although there is no one "right" way to grade, there certainly are justifiable and unjustifiable grades.

Then I said, innocently as I could manage,"...and giving kids zeros as a penalty for late work or for work not turned in is a perfect example of unjustifiable grading."

He immediately went on the attack. "I've heard that the school board is about to require us to not give zeros! That's outrageous! No work, no grade! We have to teach kids to be responsible!"

I didn't know which of the four positions he took to reply to first, so I chose the easiest.

"Nope," I said, "the school board is not about to require the high school to quit giving zeros. We're in a conversational mode, and I hope people are willing to think about standards-based grading and talk it over."

"However," I followed up with, "have you given any thought to the math of zero?"

"What do you mean, the math? Zero is zero. Nothing is nothing. No work, zip. End of story."

Realizing that I had no graceful exit strategy from this conversation if my colleague proved resistant to my charm and logic, I set up a problem for him to analyze.

"Think about this," I suggested. "Everyone is familiar with a 4.0 GPA scale, right? What if the F (a zero, right?), in a 4.0 scale had the same weight as a zero in a scale of 0-100, the percent scale we use almost universally for grading?"

"What are you getting at?" he asked.

"Just this," I said. "In a 4.0 scale, A=4, B=3, C=2, D=1, and F=0. The difference between a D and an F is just one point. On the percentage scale, the difference between a D and a zero is 60 points. Does that seem proportionate to you?"

"No," he said, as the math began to register. "On a 4.0 scale, if it were equivalent to a percentage scale, the F would be, what, negative 6?!"

"That's in the ball park," I said. "Isn't it amazing that we teachers don't ask these kinds of questions more often when we talk about grading?"

"Yeah," he said thoughtfully.

"Look," I said, "here's a two-page article from the Phi Beta Kappan on the destructive effect of zeros . It's written by Doug Reeves, an international education consultant based in Colorado. He explains it far more eloquently than I can. Check it out."

The following week, I asked him if he liked the article. "Man," he said, "I am DONE with zeros!"

"Pass it on," I said, "because there's more..."

(Next up: Why Zero Isn't A Grade At All)

Okay, I am definitely sneaking this in to our Monday Meeting Madness discussion at school!