Types of Variables

This brief discussion is largely about terminology, but the reasons for discussing it are deeper than just what we call various things. Remember that experimental research refers to research in which one or more variables are changed or manipulated by the experimenter. One might even say that this variable (or these variables) are independent of other variables, such that they are changed independently of any other variables. For this reason, this manipulated variable is called the Independent Variable (IV). The variable (or variables) measured by the experimenter may or may not change as a function of what happens with the IV. In this case, one might say that this measured variable is dependent on what the manipulated variable is. For this reason, we call this variable the Dependent Variable (DV).

Now if you remember correlational research, this is the type of research in which two variables are measured and the relationship between them is investigated. The important distinction here is that neither of these two variables are manipulated or changed by the experimenter. Rather, both are merely measured. For example, if we were looking to determine whether a happy worker is a more busy worker, we would measure each worker's job satisfaction and job performance and see whether there was a tendency for one to increase while the other also increases. In this example, we are attempting to predict with one variable (job satisfaction) what the outcome of the other variable (job performance) will be. For this reason, one variable is labeled the predictor variable and the other is labeled the outcome variable. Both of these variables is measured in each and every participant in the study, and the relationship between the two is assessed using statistical analysis.