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Writing Your Research Paper: Understanding Extraneous Variables

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An extraneous variable is any factor that can influence the independent variable but is not deliberately studied in an experiment.

For example, if the dependent variable is the frequency of a certain type of noise in a dormitory, the noise level in that room can affect the results of the experiment.

A quieter room can help control the effects of this type of situational variable. Lighting in a room can also affect the results.

Some researchers use randomization to control for the effect of these variables. This allows them to balance the effects of known and unknown extraneous variables.

Using randomization, researchers ensure that the expected values will be the same in different environments. The extraneous variable is a measurable variable that affects the results of an experiment.

This variable may be in the form of socio-economic status, household support, or even the temperature of a room.

Extraneous vs Confounding Variables

The idea of extraneous vs. confounding variables is vital when studying one or more variables. While the extraneous variables could impact the outcomes of the study, they also add noise and variation to the study.

Furthermore, they can be able to cause confusion in a study, which can obscure the real impact on the dependent variable.

If you’re comparing various kinds of people, such as you’ll need to account for the participant’s age each participant because this can alter the results of the study.

In essence, extraneous variables are the ones that influence the findings of a study. They are variables that are distinct from independent variables and can provide an explanation to explain the observed distinctions.

For instance, those who are positively disposed of are more successful on memory tests as compared to those in a low mood. This is due to the people in the positive mood group are more intelligent.

Incorporating extra variables into an investigation makes it difficult to determine independent variables. They can also introduce noise and variation in the results.

For example, researchers cannot influence the mood of participants when they gather data on happy childhood experiences. In this case, researchers are unable to determine the impact of mood on the negative or positive memory associated with these experiences.

Thus, they have to eliminate the effect of other variables that affect the data in order to assess the impact of mood on the results of the study.

Extraneous Variables Examples

Extensive research in a particular field involves the use of a large number of extraneous variables, which may affect the dependent variable in some way. These variables can include plants, participants, and other external variables.

Researchers must account for these factors in their experiments or conduct a control group to measure the effects. These types of extraneous factors are known as confounding factors because they are impossible to avoid.

An extraneous variable example would include things like socio-economic backgrounds, amount of support at home, and nonverbal behavior of the researcher. These can affect the outcome of a drug test.

There are also a variety of types of extraneous variables that can influence the outcome of a study. These factors can include the amount of money and support in the home, and they can also include factors influencing the environment.

Confounding variables are any variables that alter the effects of one variable on another. These types of extraneous factors can lead to a false cause-effect conclusion.

For example, a researcher could provide a low-income student with a free textbook but give online learning to a high-income student. These students take more challenging coursework, which could result in a different outcome. In this scenario, extraneous variables can muddle results.

Other types of extraneous variables may be situational or individual-level. While these variables are not specifically studied, they can have a significant effect on the outcome of the research.

For example, the time of day when a test is given can influence the outcome. By holding these factors constant, the researcher can reduce the effects of these background factors and focus on the independent variable.

Some research methods use the quasi-experimental approach.

Other types of extraneous variables may also influence the dependent variable. The health of participants can affect the study’s results. Some of these extraneous variables may be related to the environment.

For instance, the temperature of the room can influence the participants’ responses. In this case, the controlled variables are constant. The same conditions are a constant for both variables. The effect of each type of extraneous variable can be measured by using a single data-type model.

Some extraneous variables may influence experimental results. For example, the gender of a therapist could influence the results of a study. These extraneous variables can affect the interest of the participants in science.

In some studies, these variables can affect the results of an experiment. For example, the gender of a person could influence the outcome of a test if the participant’s personality is more likely to engage in social behaviors in certain social situations.


When you are writing a research paper for your college studies, understanding extraneous variables is important in order to properly justify your findings.

Before you get started on writing your paper, take some time to go over the examples above so that you have a firm grasp of what you are aiming to prove.

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