Unit 5

Question 1

Experimental Design

Answer 1

Repeated, systematic presentation and removal of an independent variable (IV) while measuring changes in the dependent variable (DV), and holding other factors constant

Question 2

The primary goals of experimental design

Answer 2

To demonstrate a functional relationbetween the IV and DV To evaluate the interventions once they are decided upon

Question 3

Functional relation

Answer 3

Exists when changes in an antecedent or consequent stimulus class consistently alter a dimension of a response class

Question 4

Internal validity

Answer 4

The extent to which an analysis assures that measured changes in behavior are due to the manipulation and NOTdue to uncontrolled extraneous variables

Question 5

External validity

Answer 5

The extent to which a study’s results are generalizable to other subjects, settings, or behaviors

Question 6

Why Internal Validity is a Priority

Answer 6

It makes little sense to consider the generality of the effect (external validity) if extraneous variables cannot be ruled out for the effect

Question 7

Threats to internal validity

Answer 7

History
Maturation
Testing
Instrumentation
Diffusion of treatment
Regression towards the mean
Selection bias
Attrition

Question 8

History

Answer 8

Introduction of the IV may coincide with other events in the person’s life (and those other events could have produced the effects)

Question 9

Maturation

Answer 9

Natural developmental events or learning experiences may coincide with the introduction of the independent variable to produce the change

Question 10

Testing

Answer 10

Changes in the dependent variable may have come about as a function of repeated exposure to the experimental arrangements

Question 11

Instrumentation

Answer 11

Changes may reflect modifications in the measurement systems rather than effects of the IV

Question 12

Diffusion of treatment

Answer 12

Inadvertent, uncontrolled “seepage” of the treatment to control conditions or control subjects

Question 13

Regression towards the mean

Answer 13

Changes occurred because baseline measurements were NOT representative of the natural state of events; perhaps less relevant to single-case designs because of repeated measures

Question 14

Selection bias

Answer 14

The assignment of subjects to groups may have biased the outcome even in the absence of any intervention; Perhaps less relevant to single-case designs because participants serve as their own controls

Question 15

Attrition

Answer 15

The loss of subjects over time, especially if systematic, may influence the effects; Perhaps less relevant to single-case designs because participants serve as their own controls

Question 16

Minimizing Validity Threats

Answer 16

Measurement
Stability
Immediacy
Replication

Question 17

Measurement

Answer 17

Continuous assessment-collecting data on the dependent measure for an extended period of time

Question 18

Stability

Answer 18

If levels of the DV remain relatively stable over time before the independent variable is introduced, the likelihood that the change canbe attributed to the IV increases

Question 19

Immediacy

Answer 19

The more immediate the effect, the stronger the case that the IV produced it

Question 20

Replication

Answer 20

Demonstration using multiple cases; If the IV affects many subjects in the same manner, a stronger case can be made that it produced the change

Question 21

Single-Case Designs(SCD)

Answer 21

A variety of research designs that use baseline logic to demonstrate the effects of IVs on the behavior of individual subjects.

Question 22

Other names for Single-Case Designs

Answer 22

Single-subject design
Within-subjects design
Intra-subject design
Small n design

Question 23

Characteristics of Single-Case Designs

Answer 23

ndividuals serve as their own control; Each individual is exposed to each level of the IV; Changes in the IV are made once the DV has reached a steady state; Small number of subjects; Multiple and repeated measures; Usually visual data analysis

Question 24

Characteristics of Group Designs

Answer 24

Comparisons are made between groups of individuals (“control” group vs. experimental group); large number of subjects; each individual often exposed to only one level of the IV

Question 25

Advantages of Single-Case Designs

Answer 25

Dynamic change (repeated measurement and stability permit you to see patterns of behavior change); Variability (allows the examination of inter-subject and intra-subject variability); Accountability (represents the performance of an individual subject)

Question 26

Baseline

Answer 26

Assessment of the dependent variable prior to the introduction or change of the independent variable

Question 27

Functions of Baseline

Answer 27

Descriptive
Predictive
Insight
Setting targets

Question 28

Phase change

Answer 28

Movement in the analysis from one level or kind of independent variable to the next level or kind of independent variable

Question 29

A-B Design

Answer 29

Baseline phase followed by a treatment phaseEffect is demonstrated when behavior changes from one phase to the next

Question 30

Limitations of A-B Designs

Answer 30

Supports weak conclusions

Changes in behavior may be the result of extraneous variables

Question 31

Phase change logic

Answer 31

Ideally phase changes are made when behavior reaches a steady state defined by level, stability and trend.

Question 32

3 factors needed for “steady state responding”

Answer 32

Level (behavior is high or low enough to detect a change if one occurs); Stability (levels of behavior do NOT vary greatly from one measurement to the next);Trend (the behavior is NOT already changing in the predicted direction).

Question 33

Reversal Design

Answer 33

Following baseline, the IV is introduced, then withdrawn (at least once, 2 times is preferable)

Question 34

Advantages of Reversal Designs

Answer 34

Most straightforward single-casearrangement; Most powerful demonstrationof functional relations

Question 35

Limitations of Reversal Designs

Answer 35

Reversibility (some behavior changes are not reversible)
Ethical concerns of treatment reversalTime (to get stability in all phases)
Order (could be sequence effects)

Question 36

Multiple Baseline Design

Answer 36

Two or more independent baselines are established; The IV is then separately introduced in a staggered fashion to each baseline; When behavior is stable for the first baseline, the IV is introduced on the second baseline,and so on.

Question 37

3 Standard Variations of Multiple Baseline Designs

Answer 37

Multiple baseline across subjects
Multiple baseline across behaviors
Multiple baseline across settings

Question 38

Advantages of Multiple Baseline Designs

Answer 38

Useful when behavior change is notreversible
Does not require countertherapeutic behavior change to demonstrate control
Experimenter can empirically evaluate methods and interventions before applying on a larger scale

Question 39

Limitationof Multiple Baseline Designs

Answer 39

Interdependency (changing behavior in one baseline is likely to change behaviors in the other baseline even though the IV is not introduced to other baselines)

Question 40

Non-concurrent Multiple Baseline (Delayed Multiple Baseline)

Answer 40

Across individuals.

Separate baselines are taken; The baselines are staggered but not conducted at the same time

Question 41

Advantages of Non-concurrent Multiple Baseline Designs

Answer 41

Permits greater flexibility in analysis (not constrained by needing all subjects concurrently present)

Question 42

Disadvantages of Non-concurrent Multiple Baseline Designs

Answer 42

Greater interpretive challenge if behavior changes on subsequent baseline before IV is introducedNOT useful across behaviors or settings

Question 43

Multiple probe technique

Answer 43

First baseline is continuous, but subsequent baseline data collection is conducted intermittently (as “probes”), relative to the first baseline

Question 44

Advantages of Multiple Probe Design

Answer 44

Avoids “ritualistic” gathering of Baseline data
Avoids various threats
Useful when extended baseline sessions are impractical, costly, or possibly detrimental

Question 45

Disadvantages of Multiple Probe Design

Answer 45

Risks stability (perhaps infrequent probes were outliers)