Understanding Independent and Dependent Variables

independent variable dependent variable experimental design research

What are Independent and Dependent Variables?

The relationship between the independent variable (IV) and the dependent variable (DV) is critical to understanding how your experimental design may be affecting behavior. The relationship between these variables will help you predict and control behavior through your interventions. The IV is what you are manipulating, adding, removing, or changing. For example, if you start using flashcards to teach someone sight words, the flashcards are the independent variable. The DV would be the person saying the sight words, or the behavior of interest. In other words, the DV is influenced by the IV. We would want to know how the flash cards influenced the behavior of saying sight words.

Experimental Control as it Relates to the IV and DV

Experimental control, or a functional relationship, is about demonstrating cause-and-effect between what you manipulate or change (IV), and how it affects the behavior (DV). When you can reliably control the DV through manipulation, you are said to have experimental control. This is the goal of any good intervention or experiment. For example, in applied behavior analysis (ABA therapy), you might use reinforcement (IV) to increase on-task behavior (DV). If the reinforcement effectively increases on-task behavior, there is a functional relatinship, and your intervention is successful.

Confounds (Confounding Variables) and Extraneous Variables

When doing research, or designing interventions in ABA, you want to be sure and control as many variables as possible. You do this in order to prevent outside forces from affecting the outcome of your intervention, or changing your target behavior unintentionally. Variables that are not part of your experiment are considered extraneous variables. You want to control for extraneous variables as much as possible. If an extraneous variable does end up affecting your experiment or intervention, than it becomes a confound. A confounding variable is something you want to avoid because these variables threaten experimental control.

The Importance of Experimental Design

Even if you are not a researcher, and are a clinical therapist or behavior analyst, you still want to understand the basic relationship between the IV and the DV, and then the need to control your extraneous variables. This is the foundation for any successful behavior change intervention. Here at ABA Exam Review we are committed to helping future behavior analysts, and other behavior therapists, succeed on their board exams, and in their career.

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