1. QUASI-EXPERIMENTS What is a Quasi-Experiment?
What is a Single-Group Time Series Design?
Why Do Quasi-Experiments?
What is a Multiple-Group Time Series Design?
What is an Ex Post Facto Design?
What is a Cross-Sectional Design?
What is a Single-Group Posttest Only Design?
What is a Longitudinal Design?
What is a Single-Group Pretest/Posttest Design?
What is a Sequential or Cohort Design?
What is a Nonequivalent Control Group Pretest/Posttest Design?
How Are Quasi-Experiments Analyzed?

2. What is a Quasi-Experiment?
Compare subjects in different conditions on a DV
Lacks one or more criteria for an experiment (cause, comparison, control)
Interpreted like a correlational study

3. Why Do Quasi-Experiments?
Internal validity is a problem because the IV is not manipulated
It may not be possible or ethical to manipulate the IV

4. What is an Ex Post Facto Design?
Compare groups that differ on a pre-existing variable (subject variable)
Examples:
gender
personality
presence of mental disorder

5. What is a Single-Group Posttest Only Design?
Scores are measured after a treatment for one group
The treatment is not manipulated, and there is no comparison

6. What is a Single-Group Pretest-Posttest Design?
Scores are measured before and after an event or treatment
The treatment is not manipulated

7. What is a Non-Equivalent Control Group Pretest/Posttest Design?
Compare a treatment group and a control group before and after the treatment
The groups are not randomly assigned

8. What is a Single-Group Time Series Design?
Scores are measured several times before and after an event or treatment
Better than Pretest-Posttest design, because you can tell whether the change is likely to be due to a random fluctuation

9. What is a Multiple-Group Time Series Design?
Scores for a treatment and control group are measured several times before and after
The control group is not randomly assigned
Combination of Nonequivalent Control Group and Interrupted Time Series

10. What is a Cross-Sectional Design?
Compare different age groups at one point in time
The groups may differ on other variables, since age is not manipulated
cohort effects - generational history differences

11. What is a Longitudinal Design?
Measure the same group at different ages
Time-consuming
Attrition can be a problem

12. What is a Sequential or Cohort Design?
Compare different age groups at different ages
Combination of longitudinal and cross-sectional

13. How Are Quasi-Experiments Analyzed?
Choose from the same set of statistics used for experiments
Remember that you interpret differences like the study was correlational
Take into account number of conditions and whether variables are between or within subjects