A confounder is a variable that affects both the dependent/outcome variable and the independent/predictor variables, causing a spurious association.^[[Confounding - Wikipedia](https://en.wikipedia.org/wiki/Confounding)] Graphically, a confounder can be represented as follows: ![[Pasted image 20210922091229.png|250]] Confounding can surface in many different ways. A typical example is the effect of weather temperature on swimming pool visits and ice cream sales. Pool visits may be highly correlated with ice cream sales. However, it would be naive to infer that more pool visits lead to more ice cream sales. In this example, Z represents temperature, X represents pool visits, and Y represents ice cream sales. > [!info]- Last updated: September 3, 2024