Independent variable - Definition and Overview

In experimental design, an independent variable is a variable used to define treatment groups. For example, in a study of how different dosages of a drug are related to the severity of symptoms of a disease, the specific doses selected by the experimenters for investigation are the independent variable, while a measure of the severity of the symptoms of the disease is a dependent variable.

More generally, the independent variable is the thing that someone actively controls/changes; while the dependent variable is the thing that changes as a result.

When graphing a set of collected data, the independent variable is graphed on the x-axis.

Example Usage of Independent