Authentic Lessons for 21st Century Learning

Lines of Agreement

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


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Lines of Agreement

This formative assessment allows participants to select a claim and argue to defend their reasoning. This strategy can be used in a variety of ways to activate student thinking by supporting a claim with evidence.

Lines of Agreement


Students choose one side of a two-answer prompt and then brainstorm an argument. When they are ready, students line up to present and defend their arguments, questioning each other as they learn to respectfully challenge an argument and think more deeply about their own ideas.


  1. Choose a question with two opposite choices of answer. (Example: Are viruses living or non-living?)

  2. Give students some time to consider the question and commit to a claim.

  3. Students write down their ideas and explain their thinking.

  4. Then students form two lines facing each other, a line for each response.

  5. Students then share the thoughts that led them to choose the answers they did. Establish rules for this discussion (e.g., only one student may speak at a time or student lines each present an argument for their side and the other group follows with a rebuttal) and communicate them.

  6. After a compelling argument, ask if any students would like to switch lines based on what they have heard.

  7. If the argument was valid, expand on it. If the argument was invalid, and students still switched sides, address this and clarify information.

Keeley, P. (2015). Science formative assessment: 50 more strategies for linking assessment, instruction, and learning. Thousand Oaks, CA: Corwin, SAGE.