How do you know it worked

Single Subject Designs in Teaching

How do we know if our teaching is successful or change is due to chance?

Functional Relationship – a cause and effect. The target behavior changes as a result of the intervention

Functional Relationship exists between the two variables when the interventions have been systematically replicated on or more times

Variable: any number of factors involved in research. (factors related to participants, conditions, interventions)

GOAL: to control for the presence of absence of variables that may effect the outcomes

Variables

Independent: intervention being used

Dependent: behavior targeted for change

Confounding: Those variables in the environment that are not controlled but may influence the dependent variable

Components of a SSD

Baseline Measures A measure of the behavior under the

conditions that currently exist.

Provide a measure of the behavior if no intervention occurs.

Components of a SSD

Baseline Measures Why do we want a baseline to be as

stable as possible?

What are two measures of stability?VariabilityTrend

What to consider when trying to intervene?

Too much variability makes it difficult to draw conclusions

Good operational definition of the dependent variable

Naturally occurring variability

Trends in the data points No trend Ascending trend Descending trend

Components of a SSD

Intervention Measures Repeated measures of the behavior

under treatment conditions

Experimental Control insures that changes in the behavior are in fact due to the intervention and not other confounding variables…a functional relationship exists

Teaching designs

A functional relationship is not established (lack of experimental control)

Less confident assumptions can be drawn

Provide sufficient indication of behavior change

Research Designs

Allows for experimental control and the existence of a functional relationship

AB Designs

Referred to as the “Teaching design”

Consists of two phases

Data collected during intervention are compared to those collected during baseline

Advantages Disadvantages

Simple to use

Compares student performance

Cannot make confident assumptions

Good to graph acquisition obj.

Reversal Designs

Used to study the effectiveness of a single intervention (independent variable)

Consists of 4 phases Should not be used:

When dependent variable is dangerous

When dependent variable is not reversible

Advantages Disadvantages

Experimental control

Must withdraw intervention

Simple

What problems does this pose?

Reversal Designs

Repeatedly compares baseline data to intervention data

Dependent on the replication of baseline and intervention effects

Confounding variables?

Changing Criterion Design

Evaluates the one independent variable on one dependent variable

Experimental control is demonstrated by incrementally increasing or decreasing the dependent variable

Consists of two phases

Advantages Disadvantages

Functional relationship without withdrawing intervention

Must be used on behaviors that require small incremental changes

Progress oriented

Starting with small change

Changing Criterion Design

Implementation Collect baseline data Determine interim criterion for

performanceMean of the stable portion of baselineHalf the mean of the baselineHighest or lowest baseline Professional estimate

Changing Criterion Design

Demonstrating Functional Relationship Alter the number of sessions Continue with a sub-phase until a

stable rate Vary the increase Require a change in the opposite

direction

Multiple Baseline Designs

Analysis of 1 independent variable on more than 1 dependent variablesAcross behaviorsAcross settingsAcross individuals

Consists of 2 phases

Multiple Baseline Designs

Cannot be used with a behavior that calls for immediate action

When behaviors are not independent

Advantages Disadvantages

Establish a functional relationship (without reversing the intervention

Must implement across settings, people, etc. -- cumbersome

Allows the examination of one intervention on many kids

Collect baseline over extended period of time

Multiple Baseline Designs

ImplementationBaseline is collected on all conditions at the

same timeBegin intervention in first condition when

stable baseline is reachedBegin intervention in second condition when

change has occurred in the first condition

Multiple Baseline Designs

Extended BaselinesNot appropriate for some behaviorsKids may learn error responseKids may become frustratedNo instruction being delivered

Alternating Treatments Designs

Allows the comparison of the effectiveness of more than one intervention on a single dependent variable

Advantages Disadvantages

Efficient for teachers

Must implement a replication phase for functional relationship

Multiple treatment spillover

Alternating Treatments Designs

ImplementationEach condition equal number of timesSchedule of interventions should be

counterbalanced (to avoid order effects)Distinctive discriminative stimulus should

immediately precede the condition

Changing Condition Design

Implementation Interventions are introduced

sequentially. Functional relationship only if a return

to baseline occurs before C condition

Used to study the effectiveness of two or more treatments on the behavior of a student. ABC design

Advantages Disadvantages

Compare interventions

No functional relationship can be established

Cummulative effects

Analysis of Results

Visual InspectionMean of data pointsLevels of performanceTrend in performance