Experimental Design Flashcards
What are experimental designs?
The way participants are allocated to experimental groups
What are the three types of experimental design?
- Independent groups
- Repeated measures
- Matched pairs
What is the independent groups design?
- Randomly dividing a group of participants into groups through a ballot system, random number generator etc
- Each group takes part in only one condition
What are the strengths of the independent groups design?
- No order effects
- Can use same resources
- Participants unlikely to guess aim
- No need to wait between conditions
What are the weaknesses of the independent groups design?
- Can’t control participant variables
- Needs lots of participants
What is the repeated measures design?
- Recruit a group of participants and let them participate in all conditions
- All participants take part in all conditions then results are compared
What are the strengths of the repeated measures design?
- Gets rid of participant values
- Don’t need as many participants
What are the weaknesses of the repeated measures design?
- Order effects
- May not be able to perform in other condition immediately
- Needs different resources
- Participants can guess hypothesis
What is the matched pairs design?
- A group of participants are recruited in pairs of similar values that are relevant to the experiment
- Participants are then randomly assigned to each condition, splitting the pairs
- Participants are assessed according to their partners
What are the strengths of the matched pairs design?
- No order effects
- Can use same resources
- Participant variables are controlled to an extent
- Unlikely to guess aim
- No need to wait between conditions
What are the weaknesses of the matched pairs design?
- If one pair drops out, the pair is lost
- Takes a long time to find a perfect pair
- Needs a lot of participants
What are order effects?
How the order of the conditions affect the results of the experiment
What is counterbalancing?
Having one half of the sample complete the conditions in one order, and having the other half complete it in reverse to REMOVE ORDER EFFECTS
