# Correlation vs causation

Understand that correlation does not necessarily imply causality (S-ID.C.9).

Students are now experts at figuring out how closely two sets of data are correlated, but they may be susceptible to the logical fallacy that correlation implies causality. Some well-chosen tasks can warn them against drawing such a false conclusion.

## Tasks

WHAT: Students are told that “students who watched TV for an hour or more on weeknights were significantly more likely to have high blood pressure, compared to those students who watched less than an hour of TV on weeknights” and asked “Does this mean that watching more TV raises one’s blood pressure?” Requiring students to make a thorough justification is an opportunity for them to construct viable arguments and critique the reasoning of others (MP3).

WHY: Students know how to determine how closely two variables are correlated, but have not yet been asked whether correlation implies causality. Examples like this introduce the idea that two variables with a high correlation may not be causally related.