Experimental designs

What is experimental design

The way in which participants are used in an investigation

What is an independent groups design

When 2 separate groups of participants experience 2 different conditions

What is a repeated measures design

When all participants experience both conditions of the experiment

What is a matched pairs design

When participants are paired together based on a variable of the experiment and then one is placed in condition A and the other in condition B

What are evaluation points of independent groups (3)

Participants in the group are not the same in terms of participant variables - random allocation is used to deal with this

Its not cheap - each participant only produces a single result

Order effects are not a problem

What are evaluation points of repeated measures

Order effects - dealt with using counterbalancing which is where half the participants experience the conditions in one order, and the other half in another order

Demand characteristics - participants are more likely to work out the aim of the study

Fewer participants are needed and participant variables are controlled

What are evaluation points of matched pairs

Order effects and demand characteristics are not a problem because they only take part in one condition

Participants can’t be matched exactly so there could still be participant variables

Matching may be time consuming and expensive