AO1 - Types of Experimental Designs

• Independent groups design: Participants take part in one condition only, each condition has a different group of participants
• How to conduct an independent groups design:

  1. A group of participants are recruited
  2. They are split into equal sized groups
  3. A different group is allocated to each condition
• Repeated measures design: All participants take part in all/both conditions of the experiment
• How to conduct a repeated measures design:

  1. Participants complete one condition
  2. After a sufficient time lapse (an hour) they will complete the other condition
  3. The task should be different but matched on difficulty/measuring the same thing
• Matched pairs design: Participants are matched on important characteristics in the study, e.g. IQ. by giving them an appropriate test and matching two participants with the same score. Each member of the pair is then randomly allocated across each condition
• How to conduct a matched pairs design:

  1. Choose a variable to match participants on
  2. Test the participant on this variable before the study
  3. Match participants with the same scores
  4. Randomly allocate each member of the pair to one condition