Unit 3 Flashcards
Threats to internal validity
History Maturation Testing Instrumentation Diffusion of treatment Regression towards the mean Selection bias Attrition
Systematic manipulation
The repeated and systematic presentation and removal of an independent variable
While measuring the dependent variable and holding other factors constant
There is no distinction in systematic manipulation used for treatment evaluation or
Experimental design
The primary goals of systematic experimental manipulation are
To demonstrate a functional relations between the independent and dependent variables
A functional relation is said to exist when…
Changes in an antecedent or consequent stimulus class consistently alter a dimension of a response class
Systematic experimental manipulations are also used to
Evaluate the interventions once they are decided upon.
Internal validity is
The extent to which an analysis assures that measured changes in behavior are due to the manipulation and NOT due to uncontrolled extraneous variables.
External validity is
The extent to which a study’s results are generalizable to other subjects, settings or behaviors
experimental design
The repeated and systematic presentation and removal of an independent variable while measuring the dependent variable and holding other factors constant.
goals of experimental design are
- Demonstrate a functional relation between the independent and dependent variables
- Evaluate interventions.
functional relation
“When changes in an antecedent or consequent stimulus class consistently alter a dimension of a response class.”
internal validity
“The extent to which an analysis assures that measured changes in behavior are due to the manipulation and not due to uncontrolled extraneous variables.”
external validity
“The extent to which a study’s results are generalizable to other subjects, settings, or
behaviors.”
History (threat to internal validity)
“Introduction of the independent variable may coincide with other events in the person’s life; those other events could have produced the effects.”
Maturation (threat to internal validity)
“Natural developmental events or learning experiences may coincide with the introduction of the independent variable to produce the change. ”
Testing (threat to internal validity)
“Changes in the dependent variable may have come about as a function of repeated exposure to the experimental arrangements.”
Instrumentation (threat to internal validity)
“Changes may reflect modifications in the measurement systems rather than effects of the
independent variables.”
Diffusion of treatment
“Inadvertent, uncontrolled “seepage” of the treatment to control conditions or control subjects.”
regression towards the mean
“Changes may have come about because baseline measurements were not representative of the natural state of events.”
selection bias
“The assignment of subjects to groups may have biased the outcome even in the absence of any intervention. ”
Attrition
“The loss of subjects over time may influence the effects, especially if the loss was systematic.”
Ruling out threats to internal validity
- Continuous assessment
- Establishing stability of the target behavior
- Immediate effects of the independent variable
- Demonstration using multiple cases
Single-case design
single-subject design) (within-subjects design) (intrasubject design) (small n design
“A variety of research designs that use a form of experimental reasoning to demonstrate the effects of independent variables on the behavior of individual subjects. ”
Advantages of single-case designs
• Permit investigation of behavior change as a dynamic process.
• Allows the examination of intrasubject variability.
• Allows the examination of intrasubject variability.
• Lends itself well to clinical investigation and treatment accountability because participants serve as their own controls.

baseline
Assessment of the dependent variable prior to the introduction or removal of the independent variable.
Baseline logic
Functions of baseline:
• Descriptive
• Predictive
phase change logic
Phase change logic
Phase changes are made when behavior reaches a steady state (level, stability, and trend).
Type I error
“Concluding that the independent variable has produced a change in the dependent variable when in fact it has not.”
Type II error
“Concluding that the independent variable has not produced a change in the dependent variable when in fact it has.”
Advantages of visual inspection
• More likely to identify dependent variables that produce robust effects.
• Social significance of primary importance.
• Encourages the examination of variables
rather than just overall effects.
Factors involved in making data decisions based on visual analysis
- Mean (or level)
- Trend
- Latency to change
- Variability and overlap
- Phase duration
- Consistency of the effect in replication
Latency to change
“How quickly does the behavior change once the independent variable is manipulated.”
social validity assessment
“Examination of the acceptability or viability of a programmed intervention.”
factors to take into account during social validity assessment
- Social significance of goals or target behavior
- Appropriateness of the procedures
- Social importance of the results
Social validity assessment methods
- Subjective evaluation
* Social comparison
Subjective evaluations of social validity
“The client, those important in their life, or sometimes experts in a given area, evaluate whether distinct improvement have been achieved and whether the cost is worth the change.”
Social comparison of social validity
Compare the effects of the intervention on behavior to the behavior of peers.
Types of single-case designs
- Withdrawal (reversal) design
- Multiple baseline design
- Multi-element design
- Changing criterion design
- A-B design
A-B design
“A baseline phase followed by a treatment phase.”
Withdrawal (reversal) design
• Most straightforward single-case arrangement
• Most powerful demonstration of functional
relations.
Disadvantages of withdrawal (reversal) design
• Reversibility. • The ethics of intervention reversal • May require considerable time because stability required in all phases. • Dangers in the comparison of multiple treatments due to sequence effects.
Uses of withdrawal (reversal) design
• If the target behavior is reversible
• If the withdrawal of the intervention is not a
concern.
• If stability/order/time not a concern.
Multiple baseline design
“Two or more independent baselines are established. The independent variable is then separately introduced in a staggered fashion to each baseline. When behavior is stable for the first baseline, the independent variable is introduced on the second baseline, and so on.”
Types of multiple baseline designs
- Multiple baseline across subjects
- Multiple baseline across behaviors
- Multiple baseline across settings
Advantages of multiple baseline design
- Useful when behavior change is not reversible.
- Does not require counter therapeutic behavior change to demonstrate experimental control.
- Experimenter can “test” methods and interventions before applying on a larger scale.
Procedural guidelines for multiple baseline design
• Select independent but functionally similar baselines.
• Select concurrent and plausibly related baselines.
• Intervene on the most stable baseline first.
• Vary the length of the multiple baselines
significantly.
changing criterion design
“The treatment phase is divided into sub phases, each involving a different behavior criterion. Each sub phase more closely resembles the terminal behavior or goal.”
Advantages of changing criterion design
• Treatments do not have to be withdrawn.
• Does not require multiple behaviors, subjects,
or settings.
• All subjects can receive treatment after the
same length of baseline.
Disadvantages of changing criterion design
- Difficult to interpret when behavior does not closely match criteria.
- Useful only when it is meaningful to measure behavior change in stepwise increments/decrements.
- Requires considerable time and effort in planning.
Multi-element design
Alternating treatments design) (Simultaneous treatment design) (Concurrent schedule design) (Multiple schedule design
• “Rapid, sequential application and removal of one or more independent variables. Repeated measurement of behavior while the two conditions alternate rapidly.”
Advantages of multi-element design
• Ideal for comparisons of treatments.
• Can compare treatments while minimizing
sequence effects.
• Useful for highly variable behavior that
fluctuates as a function of non-experimental
variables.
• Can be more efficient (number of sessions)
than other designs.
Disadvantages of multi-element design

• Subject to multiple treatment interference.
• Unsuitable for individuals that have problems
forming discriminations.
• Unsuitable for interventions that produce
change slowly or require continuous
implementation to produce effects.
• Limited to situations in which behavior is
reversible or at least pliable.
• May require counterbalancing.
How to enhance discriminability while using multi-element designs
• Provide instructions before each session
• Reduce the number of conditions
• Use additional stimuli to facilitate
discrimination
Design combinations
“The inclusion of features from two or more designs within the same experiment.”
Advantages of design combinations
• Enhances the clarity of the results if it meets the requirements of more than one design.
Disadvantages of design combinations
• Not usually planned, rather used to make judgments about experimental control as the date evolve.
Component analysis
“Gradually withdrawing treatment components to see if behavior is maintained.”
Uses of component analysis
• Evaluate maintenance of treatment effects in the absence of the intervention.
Parametric analysis
“The systematic examination of the differential effects of a range of values of the independent variable (a single independent variable).
Uses of parametric analysis
• Determine effective parametric values of consequences, such as duration or magnitude.
Probes
“The assessment of behavior on occasions when no contingencies are in effect for the behavior.”
Uses of probes
- Evaluate whether treatment effects are evident before treatment occurs.
- Evaluate whether further training is necessary.
Confounding designs interactions
“Differential effects produced by a combination of independent variables and their influence on each other.”
Types of confounding designs interactions
- Multiple-treatment interference
- Sequence effects
- Carry-over effects
Multiple-treatment interference
“When subjects are exposed to multiple treatments, the conclusions reached about a particular treatment may be restricted to that specific context.”
sequence effects
“The effects on a person’s behavior in one condition Sequence effects can be influenced by the subject’s experience in a
prior condition.”
Carry-over effects
“Patterns of behavior established in one session may inadvertently extend into a second session, even if the independent variables are very different.”
Procedural integrity
“The extent to which the independent variables are implemented as dictated by the research plan.”
Procedural integrity assessment
“A measure of the extent to which the actual application of the independent variable over the course of an experiment matches the planned description. ”
Overcoming threats to procedural integrity
• Simplifying the independent variable.
• Adequate training and practice for those
implementing treatment.
• Direct contingencies on treatment fidelity.
