What Is a Dependent Variable?

Researchers measuring dependent variable
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The dependent variable is the variable that is being measured in an experiment. For example, in a study looking at how tutoring impacts test scores, the dependent variable would be the participants' test scores.

In a psychology experiment, researchers are looking at how changes in the independent variable cause changes in the dependent variable. One way to help identify the dependent variable is to remember that it depends on the independent variable.

When researchers make changes to the independent variable, they then measure any resulting changes to the dependent variable.

If a researcher was looking at how studying influences test scores, for example, the amount of studying would be the independent variable and the test scores would be the dependent variable. The test scores vary based on the amount of studying prior to the test.

Observations About the Dependent Variable

In many psychology experiments and studies, the dependent variable is often a measure of a certain aspect of a participant's behavior. In an experiment looking at how sleep impacts test performance, the dependent variable would test performance. It is a measure of the participants' behavior. The independent variable is deemed independent because the experimenters are free to vary it as they need. The dependent variable is dubbed dependent because it is thought to depend in some way on the variations of the independent variable.

So how do researchers determine what a good dependent variable will be? Stability is often a good sign of a quality dependent variable. If the same experiment is repeated with the same participants, conditions and experimental manipulations, the effects on the dependent variable should be very close to what they were the first time around.

Examples of Dependent Variables

  • Researchers want to discover if listening to classical music helps students earn better grades on a math exam. In this example, the scores on the math exams are the dependent variable.
  • Researchers are interested in seeing how long it takes people to respond to different sounds. In this example, the length of time it takes participants to respond to a sound is the dependent variable.
  • Researchers want to know whether first-born children learn to speak at a younger age than second-born children. In this example, the dependent variable is the age at which the child learns to speak.
  • Researchers are interested in looking at how alcohol use influences reaction times while driving. The amount of alcohol a participant injects is the independent variable, while their performance on a driving test is the dependent variable.

Sources:

Kantowitz, B. H., Roediger, H. L., & Elmes, D. G. (2009). Experimental psychology. Belmont, CA: Wadsworth.

Weiten, W. (2013). Psychology: Themes and variations, 9th ed. Belmont, CA: Wadsworth.

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