Treatment Designs

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Alternating Treatments Design: Good to try to figure out if one treatment works better than the other. You do a rapid alternation of treatments, back and forth, while keeping a baseline of sorts to see which one of the treatments produces better results. Can be used for two or more interventions. A rapid alternation helps to reduce confounding variables.

If there are three or more treatments, you need to use a counter balancing design.

ABC, BCA, CAB, ABC, etc.

In these designs, it is not necessary to start with a baseline. If you do use a baseline, as always, make sure the data is stable (more time for baseline of variable data).

If you find that one of the treatments is successful, there is the ethical consideration of taking away the treatment.

The design is weaker than Withdraw design and Multiple baseline design. Does not show relationship between IV and DV because of possible carryover effects.

Advantages: Good design to figure out best of multiple treatments. He best can be determined quicker. You don’t need a stable baseline, but it is helpful. There is no withdraw factor.

Disadvantages: Multiple treatment interference. If you are working on a behaviour that doesn’t reverse, this design is not effective, as you won’t know. Not appropriate if the client can not discriminate between the treatment conditions. Sometimes it is hard to counter balance in a natural setting. Data can be ambiguous – esp. if you have data points that overlap.

Changing Criterion Design: The criterion changes as time progresses, based on national norms or what you and the teacher decide is correct for where you are.

Graphed, there is a trend line, based on the norms of the talent being measured, and your goal line in relation to that trend.

Advantages: Effective for target behaviours which increase or decrease in a stepwise fashion, but the behaviours must be, at least somewhat, in the child’s repertoire to start. Generally, this design is used when improvement will take a long time to achieve. Treatment isn’t withdrawn.

Disadvantages: Establishing the criterion level to demonstrate experimental control. You may be shooting in the dark at times. Takes a lot of planning and implementation.

Filed under: EDC 514-515 Academic Assessment for Intervention
Copyright: February, 2004 - David Profitt