Experimental research designs

Question 1

Independent Groups

Answer 1

Participants within the study are randomly allocated to either the experimental or control group
Advantages:
- No pre testing, so less time consuming
- No order effects
- Less attrition
- Likely to result in two equivalent groups
Disadvantages
- Less control over participant characteristics

Question 2

Repeated measures design

Answer 2

Participants within the study are in both the experimental and the control groups
Advantages
- Lowers participant variables
- Requires a smaller number of participants
Disadvantages
- Order effects can be evident
- does not control demand characteristics (participants can guess what they’re being tested on)
- Participant attrition, if spread over time

Question 3

Matched participants

Answer 3

Participants within the study are pre tested to be placed into either the experimental or control group
Advantages
- Lowered order effect
- Lowers participant variables, making variables constant and eliminating potential confounding
- Lower attrition rate than repeated measures
Disadvantages
- Pre testing is time consuming and difficult
- Difficulty knowing which specific variables should be matched
- Loss of one participant means loss of whole pair
- Pre-testing could create order effect, communicate demand characteristics