Experimental designs

What is counterbalancing

a way of controlling the effects of order in a repeated measures design

• half the participants experience the condition in one order

• the other half in the opposite order

What is experimental design

different ways in which participants can be organised in relation of the experimental conditions

what is Independent groups design

when participants are allocated to different groups when each group represents one experimental condition

What is matched pairs design

when pairs of participants are first matched on some variable that may affect the dependent variable

• then one member of the pair is assigned to condition A and the other to condition B

What is random allocation

when participants are allocated to conditions in an independent groups design using a random method to control for participant variables

What is repeated measures design

when all participants take part in all conditions of the experiment

What are some limitations of independent groups

• participants ho occupy the different groups are not the same in terms of participant variables so if the researcher finds a difference in the dependent variable it may be more to do with participant variables than the effects of the IV

• they are less economical that repeated measures as each participant contributes to a single result only

• increases time and money spent on recruiting participants

What is a strength of using independent groups

• order affects are not a problem

• participants are less likely to guess the aims of the study

What are some issues of repeated measures

• each participant has to do at least two tasks and the order may be significant

• repeating 2 tasks can lead to boredom and fatigue causing deterioration in performance on the second task => matters what order the tasks are in

What are some strengths of repeated measures

• participant variables are controlled => meaning there’s a higher ecological validity

• fewer participants are needed => less time spent recruiting

What are some limitations of matched pairs

• matching is time consuming + expensive => specifically when a pre-test is required => leads to less economical than other designs

• participants only take part In a single condition => order effects and demand characteristics = less of a problem

• participants can never be matched exactly