Pre-test/Post-test controls for...
- maturation, testing,
- interactions with selection,
- regression to the mean
Why use a post-test only design?
- increased protection from testing effects
- BUT lower protection from selection effects
Why use Solomon 4-group design?
main advantage is a gain in external validity
How is a single case design different from a case study?
- case study is descriptive
- no variables manipulated in CS
- no variable control in CS
What is a quasi-experimental design?
- a design where we cannot use random assignment to groups but do manipulate an IV and measure a DV
- 2 types: non-equivalent and interrupted time series