quiz 3 Flashcards
What is the difference between a quasi-experimental design and an experimental design?
They are the same, but a quasi experimental design lacks either random assignment, a comparison or both
What are the types of a quasi-experimental design?
One group design & Multi-group without randomization
What are the types of a one group design?
- One group pretest-posttest & one way repeated measure design
- Time series design
What is the difference between a one group pretest-posttest & one way repeated measure design?
The only difference is there are a couple of follow ups in the one way repeated measures
What is the One group pretest-posttest & one way repeated measure design vulnerable to?
Internal validity
When is the one group pretest-posttest & one way repeated measure design defendable?
Defendable when previous research has documented behavior of control group (known natural history)
Defendable when follow up timeframe is short
What is a time series design
It has 1 intervention, a pretest-posttest, time is the IV, and you take a series of pretest-posttest which acts as a pseudocontrol condition.
Why does a time series design have better internal validity?
Better internal validity because series of test can be compared with each other.
Types of a multiple group without randomization design?
- Nonequivalent pretest-posttest control group & historical controls
- Nonequivalent posttest only design
Characteristics of nonequivalent pretest-posttest control group & historical controls
- Includes a control and an intervention group.
- Includes a pretest, so there is some control over internal validity
- Test equivalency of groups is based on the prescores
- May be warranted ethical concerns preclude a randomized control group
Characteristics of nonequivalent posttest only design
Has a control and intervention group
No pretest, so no knowledge of where subjects started
NO way to test equivalency of groups based on pre-scores
Not really used
Single subject design (N=1 designs) are similar to
Time series design
Single subject design allows for “cause & effect” inferences due to
Rigorous planning, including reliable & valid outcome measures.
Consistent with EBP focus on individual patients
Has a control phase.
What is a control phase?
When you can see what happens without intervention.
In a single subject design, independent variables are called _____ and dependent variables are called _____
Treatment(levels=phases)
Patient response/target behavior
How does n=1 differ from case studies/series?
It differs due to repeat measurements & design phases
What are the design phases in an n=1?
Baseline & intervention
What does the baseline phase look for?
Stability and trend
What does stability do?
ideally want to observe little variability/change. If baseline variability is large, may need to obtain more measurements
What does trend indicate
indicates a change is occurring without intervention. Evaluate whether rate of change is stable or unstable.
Unlike group experimental research, n=1 timeline studies can be
flexible
Characteristics of length phase?
- Important to extend phase until stability is reached
- Minimum 3-4 data points for each phase
- best to have relatively equal phase and interval lenghts
- can use summary assessments
Characteristics of a target behavior (DV)
- Patient- focused & even subjective measures
- Needs to be quantitative & should provide proof of reliability
- Can be “time to something” “frequency of something” “standardized outcome measure”
What is single subject A B design?
Baseline phase (A) Treatment/intervention phase (B)
Advantages and disadvantages of single subject A B design
Advantages: can observe changes between A & B
Disadvantages: Unsure if B was due to some confounding or maturation effect, learned effect
What is single subject A B A design?
When treatment is applied, then removed.
Baseline (A)
Treatment/intervention: (B)
Advantages and disadvantages of single subject A B A design
Advantages: can determine if A truly caused B to occur (expose any probable confounding variable). Since target behavior should return to baseline
Disadvantages: behavior must be reversible. There are ethical issues with withdrawal treatment
Data analysis is generally based on either ____ or _____
Visual trends or variability assessment