What is an independent variable?

 A variable that you believe might influence your outcome measure. This might be a variable that you control, like a treatment, or a variable not under your control, like an exposure. It also might represent a demographic factor like age or gender. Contrast this with the definition of the dependent variable. An independent variable is a hypothesized cause or influence on a dependent variable. One way to distinguish these variables is to ask yourself what you are want to learn from this research. The dependent variable is a variable you are trying to predict. Any variable that you are using to make those predictions is an independent variable. A recently published research study examined the relationship of dietary fat consumption and the development of ischemic stroke in a cohort of 832 men who were free of cardiovascular disease at baseline (1966-1969) and who were followed for a twenty year period. In this study, the independent variables were:

Creative Commons License This work is licensed under a Creative Commons Attribution 3.0 United States License. It was written by Steve Simon on 2002-10-11, edited by Steve Simon, and was last modified on 2008-01-11. This page needs minor revisions. Category: Definitions, Category: Hypothesis testing.