What are the pros and cons of a within-subjects design?
Within-subjects designs have many potential threats to internal validity, but they are also very statistically powerful.
- Only requires small samples
- Statistically powerful
- Removes the effects of individual differences on the outcomes
- Internal validity threats reduce the likelihood of establishing a direct relationship between variables
- Time-related effects, such as growth, can influence the outcomes
- Carryover effects mean that the specific order of different treatments affect the outcomes