Authentic Lessons for 21st Century Learning

I Used to Think... But Now I Know

K20 Center | Published: September 16th, 2020 by K20 Center


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I Used to Think... But Now I Know

This strategy asks participants to compare their thoughts from the beginning of a lesson to the ideas they have after completing the lesson.

I Used to Think... But Now I Know


Students list their understanding of a topic before a lesson and then list their understanding of a topic after the lesson so they can see what they learned from the instruction. This strategy gives the instructor an opportunity to see how students' thinking changes as a result of instruction and whether or not participants recognize their own prior misunderstandings. The results can help instructors determine the effectiveness of their instruction. 


  1. Students divide a piece of paper into two columns with the headings "I Used to Think . . ." on the left side and "But Now I Know" on the right.

  2. Present students with a topic or concept to reflect on before the lesson begins and complete the left side of the table by writing down their thoughts.

  3. After instruction, have students reflect on the topic or concept again, completing the right side of the table with their thoughts.

  4. These responses can then be turned in to the teacher or shared with a partner or with the whole class.

Keeley, P., & Tobey, C. R. (2011). Get the facts. In Mathematics Formative Assessment: 75 Practical Strategies for Linking Assessment, Instruction, and Learning (pp. 109-111). Thousand Oaks, CA: Corwin, SAGE.