What Is a Dependent Variable?

What is the dependent variable?

The dependent variable is the variable being measured or tested in an experiment. For example, in a study looking at how tutoring affects test scores, the dependent variable would be the participants’ test scores, since that’s what is being measured.

In a psychology experiment, researchers study how changes in one variable (the independent variable) change the dependent variable. Manipulating the independent variables and measuring the impact on the dependent variables allows researchers to draw conclusions about cause-and-effect relationships.

Independent variable vs Dependent variable

Tests can range from simple to quite complex, so sometimes it can be a bit confusing knowing how to define independent and dependent variables. Here are some questions to help you figure out which one it is.

What variable is the tester measuring?

Remember that the dependent variable is the variable being measured. So if the test is trying to see how one variable affects another, the variable being affected is the dependent variable.

In many experiments and psychological studies, the dependent variable is a measure of a certain aspect of a participant’s behavior. In an experiment looking at how sleep affects test performance, the dependent variable will be test performance.

What variable does the tester manipulate?

The independent variable is “independent” because testers are free to change it as they need. This could mean changing the amount, time, or type of variable that study participants receive as a treatment or condition.

For example, it is not uncommon for treatment-based studies to show that some subjects receive certain treatments while others receive no treatment at all. In this case, the processing is an independent variable because it is the variable that is manipulated or changed.

How to choose a dependent variable

How do researchers determine what a good dependent variable would be? There are a few key characteristics that a scientist might consider.

The stability

Stability is often a good sign of a higher quality dependent variable. If the same experiment is repeated with the same participants, experimental conditions and manipulations, the effects on the dependent variable will be very close to what they occur on the first time.

Complication

A researcher can also choose dependent variables based on the complexity of their study. Although some studies may have only one dependent variable and one independent variable, there may be several of each type.

Researchers may also want to learn how changes in an independent variable affect several dependent variables. For example, imagine an experiment in which a researcher wanted to find out how the clutter of a room affects people’s levels of creativity.

This study may also want to see how the clutter of a room can affect a person’s mood. The clutter of a room will be the independent variable, and the study will have two dependent variables: creativity and mood.

Operational ability

Operation is defined as “transforming a structure into its expression.” In a word, it refers to how a variable will be measured. So a good dependent variable is one that you can measure.

For example, if burnout is measured, researchers may decide to use the Maslach Burnout Inventory. If they are measuring depression, they can use the Patient Health Questionnaire-9 (PHQ-9).

Example of dependent variable

When you are learning how to define dependent variables in an experiment, it can be helpful to see examples. These are just a few examples of psychological research using dependent and independent variables.

• How does the amount of time spent studying affect test scores? In this example, the amount of learning will be the independent variable and the test score will be the dependent variable. The researcher can also change the independent variable by assessing how age or gender affects test scores.
• How does stress affect memory? In this example, the dependent variable might be the score on the memory test and the independent variable might be the ability to be exposed to a stressful job.
• How does a particular treatment technique affect the symptoms of a psychological disorder? In this case, the dependent variable could be defined as the severity of the symptoms the patient is experiencing, while the independent variable would be the use of a particular therapy.
• Does listening to classical music help students do better on math tests? In this example, scores on math exams are the dependent variable and classical music is the independent variable.
• How long does it take 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, while sound is the independent variable.
• Do first-born babies learn to speak at a younger age than second-borns? In this example, the dependent variable is the age at which the child learns to speak and the independent variable is whether the child is the first or second child.
• How does alcohol use affect reaction time while driving? The amount of alcohol the participants drank was the independent variable, while their performance on the driving test was the dependent variable.

A very good word

Understanding what the dependent variable is and how it is used can be helpful for explaining the different types of research you encounter in different contexts. When you are trying to determine which variable it is, remember that the independent variables are the cause while the dependent variables are the effect.