A Question Teachers Should Ask as Often as Possible

Imagine you’re back in school: math class. Your teacher has a mathematical expression on a whiteboard and would like a student to come up and solve the problem. You volunteer, because you already know the answer. It’s a complex equation, requiring you to multiply, divide, add, and subtract. You scribble down the correct answer, turning around to walk back to your desk, when your teacher stops you in your tracks and says, “Don’t forget to show your work!”

Asking high-quality questions is essential in engaging students and sustaining deep learning. In certain subjects, it’s extremely common for teachers to ask students to explain how they came to a certain conclusion, but it took me a while to incorporate this concept into my Social Studies and Reading classes.

There are several useful techniques to generate questions (see the Question Formulation Technique, this site on Socratic Seminars, this Questioning Toolkit, and this article about other types of questions). I would add one specific question to the top of the list of techniques that deepen thinking and enhance engagement: asking students “How do you know...?”

Asking this follow-up question after a student provides an answer prompts deeper thinking in a number of ways. Students have to not only consider evidence and alternative answers but also support their thinking. It moves the initial question from a place of simple recall or recognition into higher levels of thinking. Additionally, it helps me as the instructor to ensure that my students understand the concept and can justify their answers.

An Example From My Classroom

While using a projector to show students a map of the Middle East, I ask the question, “What is the relative location of Afghanistan?” A student answers, stating that Afghanistan is next to Pakistan. I instruct the class to discuss with their elbow partners, deciding whether they agree or disagree, as well as how they know for sure that the answer provided is either correct or incorrect.

I ask a second student, “Do you agree with [Student 1]’s answer, and if so, how do you know?” The second student responds that the map shows Pakistan and Afghanistan are next to each other. I push further: “But how do you know that it’s the relative location that we are talking about?” The second student has the light bulb moment: “Oh,” they respond, “because relative location is about what’s nearby, and Afghanistan is near Pakistan.”

I return to Student 1 and ask if that’s what they were thinking when they answered and if they have anything else they’d like to add. The first student agrees and adds, “I could also say that Afghanistan is northwest of Pakistan, instead of nearby.”

Drawing In the Whole Class

I have now engaged two students directly with this conversation, and all students indirectly. At the same time, I’ve made the rest of the class aware that they need to know this, too, and reviewed both the definition and the application of the concept of relative location. This significantly increases the amount of participation and engagement—especially if paired with something like Think Pair Share or elbow partners—and helps me formatively assess more students. It also establishes the norm that students need to be actively listening and paying attention to their peers’ answers, because they might be the one to get that follow-up question next.

This technique can also help students use logic rather than memorization and find relationships between concepts, as in this example:

Let’s say I ask my class which came first: the bombing of Pearl Harbor or the dropping of the atomic bombs on Hiroshima and Nagasaki. Student 1 says Pearl Harbor was first. “It was in 1941 and the bombs were in 1945,” they say.

I push further: “Yes, but without looking at the dates, how do you know that Pearl Harbor had to be before the atomic bombs?” A second student chimes in, “Oh, because Pearl Harbor got the U.S. into World War II, and the atomic bombs ended the war.”

Students worked to combine prior knowledge and current knowledge to create an answer to that question. This type of work requires them to use logic and find relationships between details, rather than simply memorizing information. You can also use “How do you know?” to engage students in some historical detective work. Present a hypothetical and ask them to determine if the scenario is possible or impossible. For example, “John turned 45 in 2021 but claims to remember watching the moon landing on TV live as it happened. Is that possible? How do you know?”

And during reading activities, try employing this technique by asking students to identify where in the text they can find support for their answer to a question. When asking review questions about a text that students have been working with, you can encourage them to explain what tipped them off to the question’s answer. This allows students to take the lead in identifying where to find information that supports their thinking, like page numbers, and key parts of the text that offer clues, like the chapter header.

While not earth-shatteringly new, complex, or profound, adding this simple follow-up question into my repertoire is something that I need to remind myself to do on a regular basis. Asking “How do you know?” slows down the pace of my inquiry in the classroom but generates additional depth from students’ answers, increasing engagement and participation.

This is the kind of questioning, visible thinking, student-to-student dialogue, and justification of answers that the Danielson evaluation rubric calls for in Domains 3b and 3c—it’s well worth the time.