CCSS.Math.Content.HSS-ID.C.9

MathGrades 9–12Interpreting Categorical and Quantitative Data

The standard

Distinguish between correlation and causation.

Common Core State Standards for Mathematics

What this standard means

Students need to tell when two variables move together and when one variable actually causes a change in the other. They should read graphs, tables, and short claims, then explain whether the evidence shows a relationship only or supports a cause-and-effect claim.

Mastery looks like students using words like “associated with,” “may be caused by,” and “does not prove” correctly. They can name lurking variables and explain why an experiment gives stronger evidence than an observational study. Students often get stuck when a graph has a strong pattern, because they assume the first variable caused the second.

Ways to teach it

  • Give pairs cards with scatterplots and headlines, then have them sort each into correlation only or possible causation with one reason.
  • Ask students to write about this claim: students who eat breakfast get higher test scores, so breakfast causes better scores.
  • Show one graph and ask students to list two possible lurking variables and decide if causation is proven.
  • Use ice cream sales and drowning data to discuss how hot weather can explain two variables rising together.

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Related standards

Standard text verified against corestandards.org on July 10, 2026.

Page updated July 10, 2026.

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