4th Quiz (Res. Design) Flashcards
Establishing Cause and Effect
- Time order
- Association between IV and DV
- Nonspuriousness: No alternative explanation
Two required components for Experimental Design
- Random Assignment
2. Control group
Random Assignment
- Randomly assign participants to control or experimental group
- Often infeasible in real world practice setting
What is the purpose of random assignment?
To produce equivalent groups for experimental and control groups
True experiments are designed to maximize…
Internal validity (by having random assignment)
Quasi-experimental group design
- No random assignment
- Non-equivalent control group design
- Simple time series design
- Multiple time series design
Control group
Receives treatmetn
Strongest Experimental Design
Experimental Design
Internal Validity
Concern with causal inferences
External Validity
Involves generalizability of the study
Threats to internal validity
- History
- Maturation
- Instrumentation
- Testing
- Mortality
- Statistical regression (Regression to the mean)
- Contamination
- Selection bias
History
Events that happen during the study period that might have had an influence
Maturation
Client aged, developed or changed in some way with passing time
Instrumentation
Changes in the measurement process
Testing
Repeated testing can provide practice and improve
scores
