Independent & Dependent Variables


Independent Variables (IV) & Dependent Variables (DV)

In an experiment, the independent variable is the variable that is varied or manipulated by the researcher, and the dependent variable is the response that is measured.

An independent variable is the presumed cause, whereas the dependent variable is the presumed effect.

The IV is the antecedent, whereas the DV is the consequent.

In experiments, the IV is the variable that is controlled and manipulated by the experimenter; whereas the DV is not manipulated, instead the DV is observed or measured for variation as a presumed result of the variation in the IV.

"In nonexperimental research, where there is no experimental manipulation, the IV is the variable that 'logically' has some effect on a DV. For example, in the research on cigarette-smoking and lung cancer, cigarette-smoking, which has already been done by many subjects, is the independent variable." (Kerlinger, 1986, p.32)

When reseaerchers are not able to actually control and manipulate an IV, it is technically referred to as a status variable (e.g., gender, ethnicity, etc.). Even though researchers do not actually control or manipulate status variables, researchers can, and often do, treat them as IVs (Heppner, Kivlighan & Wampold, 1999).


"The DV refers to the status of the 'effect'(or outcome) in which the researcher is interested; the independent variable refers to the status of the presumed 'cause,' changes in which lead to changes in the status of the dependent variable…any event or condition can be conceptualized as either an independent or a dependent variable. For example, it has been observed that rumor-mongering can sometimes cause a riot to erupt, but it has also been observed that riots can cause rumors to surface. Rumors are variables that can be conceived of as causes (IVs) and as effects (DVs)." (Rosenthal & Rosnow, 1991, p. 71)

Some Examples of Independent and Dependent Variables

The following is a hypothesis for a study.

1. "There will be a statistically significant difference in graduation rates of at-risk high-school seniors who participate in an intensive study program as opposed to at-risk high-school seniors who do not participate in the intensive study program." (LaFountain & Bartos, 2002, p. 57)

IV: Participation in intensive study program. DV: Graduation rates.

The following is a description of a study.

2. "A director of residential living on a large university campus is concerned about the large turnover rate in resident assistants. In recent years many resident assistants have left their positions before completing even 1 year in their assignments. The director wants to identify the factors that predict commitment as a resident assistant (defined as continuing in the position a minimum of 2 years). The director decides to assess knowledge of the position, attitude toward residential policies, and ability to handle conflicts as predictors for commitment to the position." (LaFountain & Bartos, 2002, p. 8)

IV: knowledge of position, attitude toward policies, and ability to handle conflicts. DV: commitment to position (continuing in position for 2 years or not continuing).

References

Heppner, P. P., Kivlighan, D. M., Jr., & Wampold, B. E. (1999). Research design in counseling (2nd ed.). New York: Brooks/Cole.

Kerlinger, F. N. (1986). Foundations of behavioral research (3rd ed.). Fort Worth: Holt,
Rinehart and Winston, Inc.

LaFountain, R. M., & Bartos, R. B. (2002). Research and statistics made meaningful in
counseling and student affairs
. Pacific Grove, CA: Brooks/Cole.

Rosenthal, R., & Rosnow, R. L. (1991). Essentials of behavioral research: Methods and data
analysis
(2nd ed.). New York: McGraw-Hill, Inc.