As an introduction to variables, we can examine two primary types: Dependent and Independent.
Dependent variables are those outcomes measures that are important to us in our study. These are the variables that we use to claim that one approach performs better (or worse) than another approach. For example, if we develop a new method for providing feedback on student programming assignments and we believe our new method will lead to higher programming grades for our students compared with the existing approach, then grades on programming assignments is our dependent variable.
These variables are the items in the study that change and typically describe the concepts that we want to understand in the study. Sometimes these variables are referred to as treatments. In the example above, the method for providing feedback on programming assignments would be our independent variable.
There are two overall types of independent variables: Controlled and Uncontrolled. Controlled variables are those independent variables that we have control over which value they take. In the example described above, the method for providing feedback on programming assignments is a controlled variable because the researcher can decide which type of feedback the students receive. Uncontrolled variables are those independent variables that, while they may change among the participants in a study, the researcher cannot control them. An example of this type of variable is experience. In a study, the researcher typically cannot control what type of experience or background someone has when they begin the study. Later in the module we will talk more about approaches for managing uncontrolled variables.