Directions for teachers

Use this short activity as a warm-up or exit ticket in class. The activity asks students to discuss confounding factors in their own lives and in science research and learn why it is important to identify and control for them.

Confounding factors

1.Think about a recent athletic, musical, theatrical or other performance or presentation you have given. What are factors or extraneous variables that impacted your performance? Did you try to control for these factors? If so, how? Is it important to control for these factors? Why or why not?

Student answers will vary.

2. What is a confounding factor or extraneous variable in scientific research? Why should possible confounding factors be controlled for in a research study? What’s the result of having confounding factors that aren’t controlled for?

Confounding variables are factors other than the independent variable that may also affect the dependent variable. A good experiment should have one dependent variable and one or maybe two independent variables with value ranges that are methodically tested in the experiment. Confounding variables should be minimized by the experimental design, and any remaining confounding factors should be accounted for when the results are analyzed. If confounding factors aren’t controlled, data collected may present false or invalid relationships.