The right way to do it is "if you don't agree with your grade, give me your paper and I will look at it more carefully. Of course I'm not just going to look at the question you're contending, but all of them. Your grade may go up, but it also may go down. Do you wish to wager?"
A very good high school math teacher of mine did this.
I think he did not get very many takers; the students were never confident that they would not lose more undeserved marks in the other question to more than offset any gain.
The right way to do it is "if you don't agree with your grade, give me your paper and I will look at it more carefully. Of course I'm not just going to look at the question you're contending, but all of them. Your grade may go up, but it also may go down. Do you wish to wager?"
A very good high school math teacher of mine did this.
I think he did not get very many takers; the students were never confident that they would not lose more undeserved marks in the other question to more than offset any gain.