Experimental Designs Flashcards
What is the experimental design
Refers to the different ways in which participants can be organised based on their conditions
A01 independent groups
This is where each participant takes part in only one condition
A03 independent groups
Strengths - low chances of participants implementing demand characteristics because they are unlikely to figure out the aim of the research as they are only taking part in one condition so are unlikely to know the IV.
Weakness - less economical as more participants are required to take part because there is more than one group HOWEVER, the groups can perform their conditions simultaneously saving more time
Participant variables are not controlled which may mean that results are directly not comparable between the two groups as different participants are taking part
Issue of allocating participants into different groups without experimenter bias HOWEVER this can be solved by using random allocation i.e. a random number generation to control unconscious bias
A01 repeated measured
When the same participants take part in all conditions
A03 repeated measured
Strengths - more economical because it does not require allocating participants to groups saving time and less participants are needed to produce equivalent data HOWEVER requires more time to perform experiment since conditions are done one after the other rather than simultaneously
Results can be directly compared between each participants because the same people are taking part, reducing affects of participants variables
Weakness - causes order effects, which could arise boredom or figuring out of the aims of experiment leading to demand characteristics. Also, participants performance may improve due to practice. Order acts as a CONFOUNDING variable HOWEVER, counterbalancing can be used to control order effects by making half of the participants perform the conditions in different orders and the averaging scores.
A01 matched pairs
Participants are matched on a key participant variable like age or IQ and then placed into separate groups so that results from each group can be directly comapred
A03 matched pairs
Strengths - limits effects of participant variables because each group has similar abilities and characteristics so results can be directly compared with high validity HOWEVER the matches are never exact and there are many different participant variables that cannot all be controlled or matched
Participants only take part in one condition so demand characteristics and order effects are less of a problem
Weakness - matching participants is very timely and costly because it might take a while to employ participants of the same variable and pre-tests are needed which take time to design and analyse
Types of counterbalancing
Full counterbalance - AB and others do BA
Randomised counterbalancing - order is chosen by chance for each participant to avoid bias
ABBA
