"All the research in education says that does not work in the long run," she said to Stephen Quinn on the CBC Radio program On The Coast.
"What we want to do is to foster the internal motivation for kids to learn," she said.
Mathison said for the same reasons parents should not punish children for poor grades.
"That's unhelpful. You want to not get trapped into what we call typical behaviourist strategies."
She said parents' conversations with their children should be about content and what they are learning, not just about outcomes.
"And that means better thinkers, better learners, and down the line better for everyone beyond school."
Hear her interview with Stephen Quinn by clicking audio link: UBC professor Sandra Mathison on report cards