Multiple – Baseline Design , Multiple Probe Design

andChanging Criterion Design

Flowchart Visual of ABA

Find the baseline

Operationalize the target behavior

Identify the antecedent

Identify the consequences

Note the placeNote the Time

How to Evaluate a Behavior Modification Program

Multiple Probe

Designs

Delayed Baseline Design

Multiple -Baseline Designs

-demonstrates the effect of an intervention by showing that behavior change accompanies introduction of the intervention at different points of time.

·  The multiple-baseline design requires that baseline behavior is collected on the several people, behaviors, or settings and then the experimental treatment is successively administered to the people, behaviors, or settings. ·  The experimental treatment effect is demonstrated if a change in response occurs when the treatment is administered to each person, behavior, or setting

Key Feature baseline phase – determining the initial level of the behavior prior to the program

Design Variations

Sample Illustration Multiple Baseline Across Behaviors

Change in sleep habits of a 4 year old girl with sleep disorders .The impact of the intervention is demonstrated in a multiple baseline design across behaviors

After the baseline data were obtained on each behavior (phase1) , the intervention was intoduced (phase 2) separately across each of the different behaviors. Each behavior changed when the intervention was introduced ;with some exceptions , behavior change closely followed the application of the intervention to that behavior. Consequently the pattern of the change suggests that the intervention, rather than more general extraneous influences , accounted for that change to the final Phase 3 follow – up data were gathered .

(a) it does not require withdrawing a potentially effective intervention, (b) sequential implementation of the independent variable parallels the practice of many teachers and clinicians, (c) the concurrent measurement of multiple behaviors allows direct monitoring of generalization of behavior change, and (d) the design is relatively easy to conceptualize and implement

Advantages

Limitations

(a) if behaviors are not functionally independent, the design may not demonstrate a functional relationship even though one may exist,

(b)because verification must be inferred from the lack of change in other behaviors, the design is inherently weaker than the reversal design at demonstrating experimental control,

(c) it is more an evaluation of the independent variable’s general effectiveness than an analysis of the behaviors selected for study,

(d) it requires considerable time and resources.

Similar to multiple baseline designs, data are collected continuously during the intervention condition of the investigation; however, once a specified criterion is achieved during intervention, intermittent collection of data is initiated. .

Multiple -Probe Designs

This design is useful for evaluating the effect of instruction on skill sequences when it is unlikely that the subject will master later steps without instruction. It is also useful for situations where a prolonged baseline could have negative effects for the subject or the experiment.

There are practical advantages for using a multiple probe design, rather than a multiple baseline design, as it may not always be necessary to collect pre-intervention data continuously if a behavior is stable, or a skill has never been introduced. However, if there is variability in level or trend across a set of data collected during probes, the pre-intervention measurement must be extended until stability is established, or there is a risk of confounding results

Changing Criterion Design

-demonstrates the effect of the intervention by showing that behavior matches a criterion for performance that is set for either reinforcement or punishment.

characteristics

IndicatorsChanging criterion studies will prove particularly useful when:• The behavior in question is unlikely to change in response to an initial criterion established at the level of the terminal goal (i.e., 20 seconds, in the example provided above).• It is desirable to “shape” the final performance through successive approximations.

Contra-IndicatorsCase studies are poor choices if:• The contingencies controlling consequences cannot be easily manipulated in small increments to successively approximate the goal.• If there is reason to believe that the contingency goal would work immediately (i.e., without successive approximations), it is probably better to use a different design that tests that final goal directly.

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