Types of VariablesSeveral types of variables are commonly used in research. A variable is a quality that researchers deal with in their studies. Two common types are easily identified in the title of a research article where the study involves cause and effect.Example: The acute effects of static stretching on vertical jump performance The independent variable is the one that researchers manipulate. It is the cause of an effect being observed. In experiments, the "effects of" in the title is the clue. In this example, it is static stretching. We can guess that there is a group that performs static stretching and probably a control group (maybe more groups) in the study. The dependent variable is the one being observed. In the title of the study, the word on is the clue to the dependent variable. Vertical jump performance is being measured--it is the dependent variable. Results depend on static stretching. In some studies, qualities are attributes. In the example, the effect of gender on science achievement, gender is a quality that the participants brought to the study. It was not assigned by the researchers nor did they manipulate it. Gender is an attibute variable, although it serves as the independent one. Confounding variables are those that a researcher fails to control. They may threaten the internal validity the study. In the static stretching study, for example, scores could be affected if the equipment for measuring vertical jump performance was not calibrated properly for all participants. Related pages: Research Designs Research Terminology Scientific Method Research Contact Us
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