What variable has potential to affect the dependent variable it does not change during the experiment?

The process of examining a research problem in the social and behavioral sciences is often framed around methods of analysis that compare, contrast, correlate, average, or integrate relationships between or among variables. Techniques include associations, sampling, random selection, and blind selection. Designation of the dependent and independent variable involves unpacking the research problem in a way that identifies a general cause and effect and classifying these variables as either independent or dependent.

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Section 1: Variables
Case Examples for Independent and Dependent Variables
Section 1: Discussion Questions
Case Example for Descriptive Study Variables
See if you can identify the variables that are under investigation in the following descriptive study:
Section 1: Discussion Questions
What variable has potential to affect the dependent variable?
What variable does not change during an experiment?
What is the variable that has a potential effect on the dependent variable but is not part of the research study?
Is the dependent variable The thing that doesn't change?

The variables should be outlined in the introduction of your paper and explained in more detail in the methods section. There are no rules about the structure and style for writing about independent or dependent variables but, as with any academic writing, clarity and being succinct is most important.

After you have described the research problem and its significance in relation to prior research, explain why you have chosen to examine the problem using a method of analysis that investigates the relationships between or among independent and dependent variables. State what it is about the research problem that lends itself to this type of analysis. For example, if you are investigating the relationship between corporate environmental sustainability efforts [the independent variable] and dependent variables associated with measuring employee satisfaction at work using a survey instrument, you would first identify each variable and then provide background information about the variables. What is meant by "environmental sustainability"? Are you looking at a particular company [e.g., General Motors] or are you investigating an industry [e.g., the meat packing industry]? Why is employee satisfaction in the workplace important? How does a company make their employees aware of sustainability efforts and why would a company even care that its employees know about these efforts?

Identify each variable for the reader and define each. In the introduction, this information can be presented in a paragraph or two when you describe how you are going to study the research problem. In the methods section, you build on the literature review of prior studies about the research problem to describe in detail background about each variable, breaking each down for measurement and analysis. For example, what activities do you examine that reflect a company's commitment to environmental sustainability? Levels of employee satisfaction can be measured by a survey that asks about things like volunteerism or a desire to stay at the company for a long time.

The structure and writing style of describing the variables and their application to analyzing the research problem should be stated and unpacked in such a way that the reader obtains a clear understanding of the relationships between the variables and why they are important. This is also important so that the study can be replicated in the future using the same variables but applied in a different way.

Fan, Shihe. "Independent Variable." In Encyclopedia of Research Design. Neil J. Salkind, editor. (Thousand Oaks, CA: SAGE, 2010), pp. 592-594; "What are Dependent and Independent Variables?" Graphic Tutorial; “Case Example for Independent and Dependent Variables.” ORI Curriculum Examples. U.S. Department of Health and Human Services, Office of Research Integrity; Salkind, Neil J. "Dependent Variable." In Encyclopedia of Research Design, Neil J. Salkind, editor. (Thousand Oaks, CA: SAGE, 2010), pp. 348-349; “Independent Variables and Dependent Variables.” Karl L. Wuensch, Department of Psychology, East Carolina University [posted email exchange]; “Variables.” Elements of Research. Dr. Camille Nebeker, San Diego State University.

Module 3:
Objectives
Section 1
Section 2
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Section 3
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Section 4
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Section 5
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Section 6
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Quiz

Section 1: Variables

The purpose of all research is to describe and explain variance in the world. Variance is simply the difference; that is, variation that occurs naturally in the world or change that we create as a result of a manipulation. Variables are names that are given to the variance we wish to explain.

A variable is either a result of some force or is itself the force that causes a change in another variable. In experiments, these are called dependent and independent variables respectively.

When a researcher gives an active medication to one group of people and a placebo, or inactive medication, to another group of people, the independent variable is the medication treatment. Each person's response to the active medication or placebo is called the dependent variable.

This could be many things depending upon what the medication is for, such as high blood pressure or muscle pain. Therefore, in experiments, a researcher manipulates an independent variable to determine if it causes a change in the dependent variable.

As we learned earlier in a descriptive study, variables are not manipulated. They are observed as they naturally occur and then associations between variables are studied. In a way, all the variables in descriptive studies are dependent variables because they are studied in relation to all the other variables that exist in the setting where the research is taking place. However, in descriptive studies, variables are not discussed using the terms "independent" or "dependent." Instead, the names of the variables are used when discussing the study. For example, there is more diabetes in people of Native American heritage than people who come from Eastern Europe. In a descriptive study, the researcher would examine how diabetes (a variable) is related to a person's genetic heritage (another variable).

Definition: A variable is either a result of some force or it is the force that causes a change in another variable. In experiments, these are called dependent and independent variables respectively.

Case Examples for Independent and Dependent Variables

Example 1:

In an experimental study looking at classical music exposure and reading ability in children, the researcher divided the children into two groups (Groups A and B). In Group A, the children listened to Mozart for one hour every day for one month. In Group B, parents were instructed to refrain from playing classical music around the child for one month. At the end of the month, all children were given a reading comprehension test. Those who listened to Mozart daily (Group A) scored significantly higher on the reading test. In this case, the reading comprehension test score is the dependent variable and exposure to Mozart’s music is the independent variable. This is because the test score is dependent on whether or not the child listens to Mozart’s music. The independent variable, exposure to Mozart’s music, is independent because it is something that can be manipulated or changed by the researcher.

Example 2:

In a study with a similar design as the previous example, researchers looked at the effects of nutrition on reading ability. In Group A, children ate at least three ounces of dark green vegetables every day for one month. In Group B, children were fed their regular diet. At the end of the month, the children took a reading comprehension test. Those who ate the green vegetables every day for one month (Group A) did not vary in their test scores when compared to Group B.

Section 1: Discussion Questions

In the second example what is the independent variable? Why?

In the second example, what is the dependent variable? Why?

Identify which variables are dependent and independent in the following examples:

Example:

Physical activity and weight loss
Dependent Variable: weight loss
Independent Variable: physical activity
Positive feedback and self confidence
Dependent Variable:
Independent Variable:
Headache and aspirin
Dependent Variable:

Independent Variable:
Muscle mass and weight-training
Dependent Variable:
Independent Variable:
Calcium consumption and bone density
Dependent Variable:
Independent Variable:
Blood pressure and salt intake
Dependent Variable:
Independent Variable:

Variables are important to understand because they are the basic units of the information studied and interpreted in research studies. Researchers carefully analyze and interpret the value(s) of each variable to make sense of how things relate to each other in a descriptive study or what has happened in an experiment.

Definition: Variables are characteristics studied in research that can take on different values (e.g., weight, height, exposure to a substance, demographics (i.e., where you live, your ethnicity, how much income you have, medical background).

Case Example for Descriptive Study Variables

See if you can identify the variables that are under investigation in the following descriptive study:

Many children who live in the Bronx, a borough of New York City, are developing asthma. In a descriptive study investigating this problem, parents whose children have asthma are asked about whether they smoke around their child, whether they live near a freeway, whether their child regularly sees a healthcare provider, their family income level and also if there is a history in their family of asthma. Prior research has shown that these factors may have an influence on the development of asthma in children.

Section 1: Discussion Questions

What are the variables that are under investigation in this study?

If you were the researcher, what other variables would you study to see if it may contribute to developing asthma? Why?

Given the variables presented in the example and the variables that you thought of, why would these variables be useful to the researcher?

What variable has potential to affect the dependent variable?

Independent variables are what we expect will influence dependent variables. A Dependent variable is what happens as a result of the independent variable.

What variable does not change during an experiment?

Controlled Variable: A controlled variable or constant variable is a variable that does not change during an experiment.

What is the variable that has a potential effect on the dependent variable but is not part of the research study?

An independent variable is one that the researcher controls or otherwise manipulates within a study. In order to determine the relationship between dependent and independent variables, a researcher will purposefully change an independent variable, watching to see if and how the dependent variable changes in response.

Is the dependent variable The thing that doesn't change?

The dependent variable, also referred to as the Y variable or the effect variable, is the variable that changes as a result of the experiment that you're running. It's the variable that you are trying to measure through the experiment, and it's the variable that you don't ever directly change.