What Are Experimental Designs?

Experimental Design (Task List 5 Section D)

In ABA there are so many different experimental designs. So let the bitches talk you through it SNABA style!

A-B Design: This design contains two phases, a baseline condition followed by an intervention condition. This is sometimes useful but does not provide verification or prediction of continued responding.

Real World Example

Joan has a neighbor that gives her the creeps. She caught him several times staring at her through the chain link fence. She decides to install high vinyl fences so that her neighbor can no longer stare at her. The thing is, once they are installed, she doesn’t know if the behavior continues or would continue if she returned to the chain link fence.

Clinical Example

Tim collects initial data on his first grader’s reading performance for CVC words. Then he teaches them how to decode CVC words and common word families. He continues to monitor and score the reading performance of his first graders since implementing the reading intervention. Since it is difficult to take away an intervention that was taught as a skill, it is difficult to reverse or take away.

Reversal Design: the reversal design contains repeated measures of the behavior in a setting with at least three phases, baseline, intervention and a return to baseline. This can continue past these three phases to include more reversals and introduction of the intervention phases.

Real World Example

Ok so we’ve all done it. Or I’ll say that most of us have done it. You are with your significant other and they treat you like shit. You break up with them and you feel so much better about yourself! Yaaaasssss QUEEN. But then, you go back to your Ex and guess what you feel like shit again. But I mean it worked for Jen and Ben right!?

Clinical Example

Janet, a BCBA and SPED teacher observed that her student struggled with achieving the correct pencil grip while writing. She implemented a simple intervention of using a grip that was recommended by an Occupational Therapist. The writing of her student improved almost instantly. She decided to test to see if it was indeed the grip that had improved the writing and not just additional practice with writing in school. She removed the pencil grip for one assignment and noted that the legibility of the writing returned to baseline levels.

Multielement Design: also referred to as an alternating treatments design, this design compares two or more interventions and compares the effect on the target behavior.

Real World Example

Tyler enjoys going to different local breweries. One of the biggest issues is he never knows what to order from a new spot. His go to solution is to order a beer flight with a variety of beers to taste from and then he continues to order whichever flute he drank the most of.

Clinical Example

Tim wants to implement an intervention on his client’s eating behavior. He researches the topic and consults with his mentor to discover three possible interventions that are sound and feasible. He decides to conduct a multi-element design where he alternates the treatments and evaluate how his learner responds to each version of the intervention in terms of eating. Whichever intervention produces the most food consumed will be the intervention that Tim continues to use.

Multiple Baseline Design: In this design, multiple baseline measures occur at the same time on two or more behaviors (settings or people). Once stable baseline data has been achieved, the independent variable is implemented to one of the behaviors (settings or people) while the other conditions remain in baseline. After great change occurs in the intervention of one behavior (setting or person) the independent variable is applied to the next behavior (setting or person) in a sequential fashion until all behaviors (settings or people) are in the intervention phase of the design.

Real World Example

Nicole recently read about intentional minutes. It’s this really simple concept that suggests that if you spend 10 minutes intentionally with your pet (no distractions like technology, tv even) that the bond between the two of you increases. First, Nicole implemented intensional minutes with her dog Zoey. After 4 days she saw a noticeable difference and decided to implement it on her daughter and then her husband. Five stars, totally recommend.

Clinical Example

Josh decides to implement a break card with a student that will allow them to escape a task or activity within their classroom. He decides to only implement the intervention within the grade level classroom with the learner until it is used independently without prompts. Once the learner demonstrates independent use in the classroom, Josh implements the break card in the OT room, then the Speech room, then in various specials until the learner is able to use the break card across multiple settings.

Changing Criterion Design: this type of experimental design is used to evaluate the effects of a treatment on the gradual increase or decrease (step like fashion) of a skill that is already in the learner’s repertoire.

Real World Example

There is this really cool app called couch potato to 5k, that gradually increases the amount of movement required of its user to eventually be able to run a 5k in its entirety. The user has to be able to move on their own, and the skill has to be in their current repertoire for the app to work. They get rewarded with virtual badges all the way up to the final distance, a 5k!

Clinical Example

A BCBA gets a new client on her caseload that is witty, cheerful and says some of the brightest comments, however her peers can never hear her because she speaks at one of the quietest speaking levels she has ever heard. She implements an intervention that gradually increases the decibels on a device that turns green when the criteria is met which slowly increases the vocal level of her client’s speaking voice. Her learner contacted natural reinforcement of her peers making reciprocal comments, laughing at her jokes and approaching her in similar situations.