This article is about an assessment called "group quizzes." I titled this article "The Assessment That Changed How I Teach" because the advent of group quizzes is the most definitive and material change that has taken place in my classroom since I've noticed a substantial shift in my teaching. That shift is one in the direction of student-centered discussion, engagement in learning and self-reflection. I know that correlation does not imply causation and I've also been teaching for nearly a decade, so I'm sure this "change" can't solely be attributed to the success of an assessment strategy, no matter how fantastic it may be. Perhaps the strategy is really a catalyst for what was already set in motion by both years of experience and other events outside of my control. But I will offer this: if you are a teacher and you are even interested in shifting the focus of your classroom to center on your students and especially if you are willing or have already tried some new techniques to that end, I would say you are in precisely the position I was in when I discovered an assessment that was everything I was looking for.