Other single subject designs part 2

Another design is the A-B-A design. An A-B-A design (also known as a reversal design) involves discontinuing the intervention and returning to a baseline.

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Another design is the A-B-A design. An A-B-A design (also known as a reversal design) involves discontinuing the intervention and returning to a baseline.

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A B A

• Of course in these designs where you withdraw treatment (sometimes called reversal designs), you always restore treatment

• For example, an A-B-A-B design

HERE IS WHAT A COMPLETE A-B-A-B CHART MIGHT LOOK LIKE

Notice that there is no use of statistics here. One can see the effects of the intervention. By withdrawing the intervention, we can see empirically (through the senses), that the intervention is the cause of the change.We use statistics when we cannot directly see the results or when we can’t Trust our senses

• But why would you withdraw treatment?• Recall that “evidence-based practice”

requires that you show that it is the treatment or intervention that is producing the change.

• By removing the treatment and reintroducing it – an A-B-A-B design, we establish a causal link between the problem behavior and the intervention

• But what else could cause the change in the problem behavior?– Perhaps the stressor that causes the problem just

goes away– Sometimes people just naturally change over time– Sometimes just the act of measuring a problem

decreases its occurrence. ( a good example is how ‘calorie counting’ is used in ‘weight watchers’.)

In research, these are known as threats to internal validity. What that means simply is that other things could be causing the change and not your intervention so the experiment is invalid. you have no proof that the intervention is causing the change.

EXPERIMENTAL CONTROLSingle-subject research designs provide experimental control for most threats to internal validity and, thereby, allow confirniiuion of a functional relationship between manipulation of the independent variable and change in the dependentvariable. In most cases experimental control is demonstrated when the design documents three demonstrations of the experimental effect at three different points in time with a single participant (within-subject replication), or across different participants (inter-subject replication). An experimentaleffect is demonstrated when predicted change in the dependent variable covaries with manipulation of the independent variable (e.g., the level, and/or variability of the dataset in a phase decreases when a behavior-reduction interventionis implemented, or the level and/or variability of the dataset in A phase increases when the behavior-reduction intervention is withdrawn).Documentation of experimental control is achieved through (a) the introduction and withdrawal (or reversal) ot the independent variable; (b) the staggered introduction of the independent variable at different points in time (e.g., multiplebaseline); or (c) the iterative manipulation ol^ the independent variable (or levels of the independent variable) across observation periods (e.g., alternatingtreatments designs).

But isn’t it UNETHICAL to withhold or withdraw treatment?

• We will deal with this later in the presentation!

• But what if the behavior is so severe that treatment or intervention is needed immediately?

Sometimes an individual’s behavior is so severe that the researcher cannot wait to establish a baseline and must begin with an intervention. In this case, a B-A-B design is used. The intervention

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Sometimes an individual’s behavior is so severe that the researcher cannot wait to establish a baseline and must begin with an intervention. In this case, a B-A-B design is used. The intervention is followed by a baseline

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Sometimes an individual’s behavior is so severe that the researcher cannot wait to establish a baseline and must begin with an intervention. In this case, a B-A-B design is used. The intervention is followed by a baseline followed by the intervention.

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Notice that treatment is withdrawn for only a brief time period!

Sometimes an individual’s behavior is so severe that the researcher cannot wait to establish a baseline and must begin with an intervention. In this case, a B-A-B design is used. The intervention is followed by a baseline followed by the intervention. Notice that treatment is withdrawn for only a brief time period!

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B A B

Another alternative to a B-A-Bdesign is

THE RECONSTRUCTED BASELINE

• A reconstructed baseline is a baseline that is created by the client’s recollection of the problem or problem behavior.

• Here you do not directly measure the client’s problem, but measure indirectly through the client (or parents or teachers etc) self-report of what the problem was like before they came to you.

• This can be done through a thorough assessment (how does the client DO the problem?) when meeting with the client.

• A reconstructed baseline has the same dimensions as a direct baseline measurement. It is:– Thorough– Specific (frequency, duration or magnitude)– Measurable (quantifiable)– observable– Valid – it measures the problem and what you are trying to

change– Sensitive to changes– individualizedMany practitioners use a reconstructed baseline

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Condition change line

Data pointsData path

Measure of timeUnit of time

Dependent measure Condition identifications Independent variable

Regardless of the research design, the line graphs used to illustrate the data contain a set of common elements.

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Condition change line

Data pointsData path

Measure of timeUnit of time

Dependent measure

problem

Condition identifications Independent variable

intervention

Regardless of the research design, the line graphs used to illustrate the data contain a set of common elements. Please read Chapter 14 in your text to learn more about Single-Subject Research and other Single-Subject Research Designs.

BUT ISN’T IT UNETHICAL (AND CRUEL) TO WITHDRAW

TREATMENT?• Most of the time, it is!• It is not, when the problem is not

debilitating• Or when withdrawing treatment helps the

client SEE the importance of continuing treatment

ARE THERE ALTERNATIVES TO WITHDRAWING TREATMENT?

YES!

AN A-B-C RESEARCH DESIGN

• “A” PHASE = BASELINE• “B” PHASE = INTERVENTION OR

TREATMENT. (NOTICE THAT SO FAR NOTHING IS DIFFERENT)

• “C” PHASE = 1. EITHER A LESSENING OF THE INTERVENTION (RECALL THE EXAMPLE OF PRAISE AS AN INTERVENTION. HERE ‘PRAISE’ WOULD BE LESSENED TO ‘GIVING PRAISE’ AT THE END OF ONE CLASS PERIOD RATHER THAN EVERY TIME THE CHILD DOES SOMETHING RIGHT) OR 2. ADDING ANOTHER INTERVENTION OR TREATMENT COMPONENT IN ADDITION TO THE ONE YOU ARE ALREADY USING IN THE “B” PHASE.

MULTIPLE BASELINE RESEARCH DESIGNS

• Multiple baseline designs involve 2 or more participants, two or more settings that the problem occurs in or two or more problem behaviors

• Does not require a reversal or withdrawal• Relies on staggered implementation of

intervention to demonstrate cause-effect• Participants’ behavior should change only

when the intervention is introduced

Multiple baseline with different subjects

At the very least, you should be able to use a simple A-B design

BaselineA

TreatmentB

Eye Contact

Time in WeeksAbove is an example of a design working with someone who has a “social phobia’ or shyness. Notice that we are working only with one problemComponent of shyness; “eye contact”

BaselineA

TreatmentB

Making small talk

Time in WeeksAbove is an example of a design working with someone who has a “social phobia’ or shyness. Notice that we are working only with one problem Component of shyness; “making small talk” after the client can establish some eye contact. YOU DO NOT HAVE TO WAIT UNTIL THE FIRST PROBLEM BEHAVIOR IS SOLVED TO BEGIN THE SECOND INTERVENTION; JUST MAKE SURE IT IS IMPROVING

However, we could turn this into a ‘multiple baseline’ by adding another “problem behavior” that is a component of shyness AFTER AND ONLY AFTER eye contact has shown some improvement (MAYBE THE THIRD WEEK OF TX)

BaselineA

TreatmentB

GOING OUT WITH FRIENDS

Time in WeeksThus in 5 or 6 sessions, we have begun to treat and measure three changes in problem behaviors that are components ofShyness. With a multiple baseline, we treat begin the treatment of problem behaviors, one at a time.

In the 5th session we could add another “problem behavior” that is a component of shyness; going out with friends

• One can also use a multiple baseline with different clients, rather than the problem behaviors of a single client

• Or the problem behavior of one client in different settings. For example,with a child who mis-behaves ‘everywhere’, we might first focus on behavior at school, then the same behavior at home, then the same behavior in social situations.

• The important thing is that the baselines and interventions are ‘staggered’ to show a ‘causal relationship between the dependent variable (the problem) and the independent variable (the treatment)

Multiple baseline

NOTICE

HowTxIs

STAGGEREd

Or problem #1

Or problem #2

Or problem #3